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  • 3D Mesh Joining

    - by morlst
    I have 2 (or more) intersecting meshes, which require joining into 1 mesh object. I want to have some control over the resulting seam vertex insertion, so looking to write myself rather than use a library. Has anyone come across some open source code to base the algorithm on / ideas on the process? Initial impressions are: 1. Present in every 3D modelling program - mostly reinventing existing process (hence search for examples) 2. Potential for fiddly-ness around the polygon face direction and just touching conditions. (see above point)

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  • Purely functional equivalent of weakhashmap?

    - by Jon Harrop
    Weak hash tables like Java's weak hash map use weak references to track the collection of unreachable keys by the garbage collector and remove bindings with that key from the collection. Weak hash tables are typically used to implement indirections from one vertex or edge in a graph to another because they allow the garbage collector to collect unreachable portions of the graph. Is there a purely functional equivalent of this data structure? If not, how might one be created? This seems like an interesting challenge. The internal implementation cannot be pure because it must collect (i.e. mutate) the data structure in order to remove unreachable parts but I believe it could present a pure interface to the user, who could never observe the impurities because they only affect portions of the data structure that the user can, by definition, no longer reach.

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  • Opengl ES and texcoord

    - by viraptor
    Hi, I've got some code which I would like to translate into Opengl ES. I'm not experienced with it however, so here it goes. The original code does a loop like this: glBegin(GL_TRIANGLES); for(i=0; i<num_triangles; i++) { glNormal(...); glTexCoord2f(...); glVerted3fv(...); glTexCoord2f(...); glVerted3fv(...); glTexCoord2f(...); glVerted3fv(...); } glEnd(); So that's ok - I can change the vertex handling for each triangle in the loop, into the standard: glEnableClientState (GL_VERTEX_ARRAY); glVertexPointer (3, GL_SOMETHING, 0, verts); glDrawArrays (GL_TRIANGLES, 0, 3); But how do I add the texcoord setting into this example?

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  • Weakly connected balanced digraph

    - by user1074557
    How can I prove that if a balanced digraph is weakly connected, then it is also strongly connected? (balanced digraph means that for every node, it's indegree and outdegree is the same and weakly connected means the non-directed version of this graph is connected). What I can think of so far is: if the graph is balanced, it means it is a union of directed cycles. So if I remove any cycle, it will stay balanced. Also each vertex in the cycle has one edge coming into it and one edge leading out of it.. Then I guess I need to use some contradiction or induction to prove that the graph is strongly connected.. That's where I confused.

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  • In a C++ template, is it allowed to return an object with specific type parameters?

    - by nieldw
    When I've got a template with certain type parameters, is it allowed for a function to return an object of this same template, but with different types? In other words, is the following allowed? template<class edgeDecor, class vertexDecor, bool dir> Graph<edgeDecor,int,dir> Graph<edgeDecor,vertexDecor,dir>::Dijkstra(vertex s, bool print = false) const { /* Construct new Graph with apropriate decorators */ Graph<edgeDecor,int,dir> span = new Graph<edgeDecor,int,dir>(); /* ... */ return span; }; If this is not allowed, how can I accomplish the same kind of thing?

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  • OpenGL performance on rendering "virtual gallery" (textures)

    - by maticus
    I have a considerable (120-240) amount of 640x480 images that will be displayed as textured flat surfaces (4 vertex polygons) in a 3D environment. About 30-50% of them will be visible in a given frame. It is possible for them to crossover. Nothing else will be present in the environment. The question is - will the modern and/or few-years-old (lets say Radeon 9550) GPU cope with that, and what frame rate can I expect? I aim for 20FPS, but 30-40 would be nice. Would changing the resolution to 320x240 make it more probable to happen? I do not have any previous experience with performance issues of 3D graphics on modern GPUs, and unfortunately I must make a design choice. I don't want to waste time on doing something that couldn't have worked :-)

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  • Inflector for .NET

    - by srkirkland
    I was writing conventions for FluentNHibernate the other day and I ran into the need to pluralize a given string and immediately thought of the ruby on rails Inflector.  It turns out there is a .NET library out there also capable of doing word inflection, originally written (I believe) by Andrew Peters, though the link I had no longer works.  The entire Inflector class is only a little over 200 lines long and can be easily included into any project, and contains the Pluralize() method along with a few other helpful methods (like Singularize(), Camelize(), Capitalize(), etc). The Inflector class is available in its entirety from my github repository https://github.com/srkirkland/Inflector.  In addition to the Inflector.cs class I added tests for every single method available so you can gain an understanding of what each method does.  Also, if you are wondering about a specific test case feel free to fork my project and add your own test cases to ensure Inflector does what you expect. Here is an example of some test cases for pluralize: TestData.Add("quiz", "quizzes"); TestData.Add("perspective", "perspectives"); TestData.Add("ox", "oxen"); TestData.Add("buffalo", "buffaloes"); TestData.Add("tomato", "tomatoes"); TestData.Add("dwarf", "dwarves"); TestData.Add("elf", "elves"); TestData.Add("mouse", "mice");   TestData.Add("octopus", "octopi"); TestData.Add("vertex", "vertices"); TestData.Add("matrix", "matrices");   TestData.Add("rice", "rice"); TestData.Add("shoe", "shoes"); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Pretty smart stuff.

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  • formula for replicating glTexGen in opengl es 2.0 glsl

    - by visualjc
    I also posted this on the main StackExchange, but this seems like a better place, but for give me for the double post if it shows up twice. I have been trying for several hours to implement a GLSL replacement for glTexGen with GL_OBJECT_LINEAR. For OpenGL ES 2.0. In Ogl GLSL there is the gl_TextureMatrix that makes this easier, but thats not available on OpenGL ES 2.0 / OpenGL ES Shader Language 1.0 Several sites have mentioned that this should be "easy" to do in a GLSL vert shader. But I just can not get it to work. My hunch is that I'm not setting the planes up correctly, or I'm missing something in my understanding. I've pored over the web. But most sites are talking about projected textures, I'm just looking to create UV's based on planar projection. The models are being built in Maya, have 50k polygons and the modeler is using planer mapping, but Maya will not export the UV's. So I'm trying to figure this out. I've looked at the glTexGen manpage information: g = p1xo + p2yo + p3zo + p4wo What is g? Is g the value of s in the texture2d call? I've looked at the site: http://www.opengl.org/wiki/Mathematics_of_glTexGen Another size explains the same function: coord = P1*X + P2*Y + P3*Z + P4*W I don't get how coord (an UV vec2 in my mind) is equal to the dot product (a scalar value)? Same problem I had before with "g". What do I set the plane to be? In my opengl c++ 3.0 code, I set it to [0, 0, 1, 0] (basically unit z) and glTexGen works great. I'm still missing something. My vert shader looks basically like this: WVPMatrix = World View Project Matrix. POSITION is the model vertex position. varying vec4 kOutBaseTCoord; void main() { gl_Position = WVPMatrix * vec4(POSITION, 1.0); vec4 sPlane = vec4(1.0, 0.0, 0.0, 0.0); vec4 tPlane = vec4(0.0, 1.0, 0.0, 0.0); vec4 rPlane = vec4(0.0, 0.0, 0.0, 0.0); vec4 qPlane = vec4(0.0, 0.0, 0.0, 0.0); kOutBaseTCoord.s = dot(vec4(POSITION, 1.0), sPlane); kOutBaseTCoord.t = dot(vec4(POSITION, 1.0), tPlane); //kOutBaseTCoord.r = dot(vec4(POSITION, 1.0), rPlane); //kOutBaseTCoord.q = dot(vec4(POSITION, 1.0), qPlane); } The frag shader precision mediump float; uniform sampler2D BaseSampler; varying mediump vec4 kOutBaseTCoord; void main() { //gl_FragColor = vec4(kOutBaseTCoord.st, 0.0, 1.0); gl_FragColor = texture2D(BaseSampler, kOutBaseTCoord.st); } I've tried texture2DProj in frag shader Here are some of the other links I've looked up http://www.gamedev.net/topic/407961-texgen-not-working-with-glsl-with-fixed-pipeline-is-ok/ Thank you in advance.

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  • Camera rotation - First Person Camera using GLM

    - by tempvar
    I've just switched from deprecated opengl functions to using shaders and GLM math library and i'm having a few problems setting up my camera rotations (first person camera). I'll show what i've got setup so far. I'm setting up my ViewMatrix using the glm::lookAt function which takes an eye position, target and up vector // arbitrary pos and target values pos = glm::vec3(0.0f, 0.0f, 10.0f); target = glm::vec3(0.0f, 0.0f, 0.0f); up = glm::vec3(0.0f, 1.0f, 0.0f); m_view = glm::lookAt(pos, target, up); i'm using glm::perspective for my projection and the model matrix is just identity m_projection = glm::perspective(m_fov, m_aspectRatio, m_near, m_far); model = glm::mat4(1.0); I send the MVP matrix to my shader to multiply the vertex position glm::mat4 MVP = camera->getProjection() * camera->getView() * model; // in shader gl_Position = MVP * vec4(vertexPos, 1.0); My camera class has standard rotate and translate functions which call glm::rotate and glm::translate respectively void camera::rotate(float amount, glm::vec3 axis) { m_view = glm::rotate(m_view, amount, axis); } void camera::translate(glm::vec3 dir) { m_view = glm::translate(m_view, dir); } and i usually just use the mouse delta position as the amount for rotation Now normally in my previous opengl applications i'd just setup the yaw and pitch angles and have a sin and cos to change the direction vector using (gluLookAt) but i'd like to be able to do this using GLM and matrices. So at the moment i have my camera set 10 units away from the origin facing that direction. I can see my geometry fine, it renders perfectly. When i use my rotation function... camera->rotate(mouseDeltaX, glm::vec3(0, 1, 0)); What i want is for me to look to the right and left (like i would with manipulating the lookAt vector with gluLookAt) but what's happening is It just rotates the model i'm looking at around the origin, like im just doing a full circle around it. Because i've translated my view matrix, shouldn't i need to translate it to the centre, do the rotation then translate back away for it to be rotating around the origin? Also, i've tried using the rotate function around the x axis to get pitch working, but as soon as i rotate the model about 90 degrees, it starts to roll instead of pitch (gimbal lock?). Thanks for your help guys, and if i've not explained it well, basically i'm trying to get a first person camera working with matrix multiplication and rotating my view matrix is just rotating the model around the origin.

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  • OpenGL - Cascaded shadow mapping - Texture lookup

    - by Silverlan
    I'm trying to implement cascaded shadow mapping in my engine, but I'm somewhat stuck at the last step. For testing purposes I've made sure all cascades encompass my entire scene. The result is currently this: The different intensity of the cascades is not on purpose, it's actually the problem. This is how I do the texture lookup for the shadow maps inside the fragment shader: layout(std140) uniform CSM { vec4 csmFard; // far distances for each cascade mat4 csmVP[4]; // View-Projection Matrix int numCascades; // Number of cascades to use. In this example it's 4. }; uniform sampler2DArrayShadow csmTextureArray; // The 4 shadow maps in vec4 csmPos[4]; // Vertex position in shadow MVP space float GetShadowCoefficient() { int index = numCascades -1; vec4 shadowCoord; for(int i=0;i<numCascades;i++) { if(gl_FragCoord.z < csmFard[i]) { shadowCoord = csmPos[i]; index = i; break; } } shadowCoord.w = shadowCoord.z; shadowCoord.z = float(index); shadowCoord.x = shadowCoord.x *0.5f +0.5f; shadowCoord.y = shadowCoord.y *0.5f +0.5f; return shadow2DArray(csmTextureArray,shadowCoord).x; } I then use the return value and simply multiply it with the diffuse color. That explains the different intensity of the cascades, since I'm grabbing the depth value directly from the texture. I've tried to do a depth comparison instead, but with limited success: [...] // Same code as above shadowCoord.w = shadowCoord.z; shadowCoord.z = float(index); shadowCoord.x = shadowCoord.x *0.5f +0.5f; shadowCoord.y = shadowCoord.y *0.5f +0.5f; float z = shadow2DArray(csmTextureArray,shadowCoord).x; if(z < shadowCoord.w) return 0.25f; return 1.f; } While this does give me the same shadow value everywhere, it only works for the first cascade, all others are blank: (I colored the cascades because otherwise the transitions wouldn't be visible in this case) What am I missing here?

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  • OpenGL - have object follow mouse

    - by kevin james
    I want to have an object follow around my mouse on the screen in OpenGL. (I am also using GLEW, GLFW, and GLM). The best idea I've come up with is: Get the coordinates within the window with glfwGetCursorPos. The window was created with window = glfwCreateWindow( 1024, 768, "Test", NULL, NULL); and the code to get coordinates is double xpos, ypos; glfwGetCursorPos(window, &xpos, &ypos); Next, I use GLM unproject, to get the coordinates in "object space" glm::vec4 viewport = glm::vec4(0.0f, 0.0f, 1024.0f, 768.0f); glm::vec3 pos = glm::vec3(xpos, ypos, 0.0f); glm::vec3 un = glm::unProject(pos, View*Model, Projection, viewport); There are two potential problems I can already see. The viewport is fine, as the initial x,y, coordinates of the lower left are indeed 0,0, and it's indeed a 1024*768 window. However, the position vector I create doesn't seem right. The Z coordinate should probably not be zero. However, glfwGetCursorPos returns 2D coordinates, and I don't know how to go from there to the 3D window coordinates, especially since I am not sure what the 3rd dimension of the window coordinates even means (since computer screens are 2D). Then, I am not sure if I am using unproject correctly. Assume the View, Model, Projection matrices are all OK. If I passed in the correct position vector in Window coordinates, does the unproject call give me the coordinates in Object coordinates? I think it does, but the documentation is not clear. Finally, to each vertex of the object I want to follow the mouse around, I just increment the x coordinate by un[0], the y coordinate by -un[1], and the z coordinate by un[2]. However, since my position vector that is being unprojected is likely wrong, this is not giving good results; the object does move as my mouse moves, but it is offset quite a bit (i.e. moving the mouse a lot doesn't move the object that much, and the z coordinate is very large). I actually found that the z coordinate un[2] is always the same value no matter where my mouse is, probably because the position vector I pass into unproject always has a value of 0.0 for z. Edit: The (incorrectly) unprojected x-values range from about -0.552 to 0.552, and the y-values from about -0.411 to 0.411.

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  • The View-Matrix and Alternative Calculations

    - by P. Avery
    I'm working on a radiosity processor in DirectX 9. The process requires that the camera be placed at the center of a mesh face and a 'screenshot' be taken facing 5 different directions...forward...up...down...left...right... ...The problem is that when the mesh face is facing up( look vector: 0, 1, 0 )...a view matrix cannot be determined using standard trigonometry functions: Matrix4 LookAt( Vector3 eye, Vector3 target, Vector3 up ) { // The "look-at" vector. Vector3 zaxis = normal(target - eye); // The "right" vector. Vector3 xaxis = normal(cross(up, zaxis)); // The "up" vector. Vector3 yaxis = cross(zaxis, xaxis); // Create a 4x4 orientation matrix from the right, up, and at vectors Matrix4 orientation = { xaxis.x, yaxis.x, zaxis.x, 0, xaxis.y, yaxis.y, zaxis.y, 0, xaxis.z, yaxis.z, zaxis.z, 0, 0, 0, 0, 1 }; // Create a 4x4 translation matrix by negating the eye position. Matrix4 translation = { 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, -eye.x, -eye.y, -eye.z, 1 }; // Combine the orientation and translation to compute the view matrix return ( translation * orientation ); } The above function comes from http://3dgep.com/?p=1700... ...Is there a mathematical approach to this problem? Edit: A problem occurs when setting the view matrix to up or down directions, here is an example of the problem when facing down: D3DXVECTOR4 vPos( 3, 3, 3, 1 ), vEye( 1.5, 3, 3, 1 ), vLook( 0, -1, 0, 1 ), vRight( 1, 0, 0, 1 ), vUp( 0, 0, 1, 1 ); D3DXMATRIX mV, mP; D3DXMatrixPerspectiveFovLH( &mP, D3DX_PI / 2, 1, 0.5f, 2000.0f ); D3DXMatrixIdentity( &mV ); memcpy( ( void* )&mV._11, ( void* )&vRight, sizeof( D3DXVECTOR3 ) ); memcpy( ( void* )&mV._21, ( void* )&vUp, sizeof( D3DXVECTOR3 ) ); memcpy( ( void* )&mV._31, ( void* )&vLook, sizeof( D3DXVECTOR3 ) ); memcpy( ( void* )&mV._41, ( void* )&(-vEye), sizeof( D3DXVECTOR3 ) ); D3DXVec4Transform( &vPos, &vPos, &( mV * mP ) ); Results: vPos = D3DXVECTOR3( 1.5, -6, -0.5, 0 ) - this vertex is not properly processed by shader as the homogenous w value is 0 it cannot be normalized to a position within device space...

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  • Drawing multiple Textures as tilemap

    - by DocJones
    I am trying to draw a 2d game map and the objects on the map in a single pass. Here is my OpenGL initialization code // Turn off unnecessary operations glDisable(GL_DEPTH_TEST); glDisable(GL_LIGHTING); glDisable(GL_CULL_FACE); glDisable(GL_STENCIL_TEST); glDisable(GL_DITHER); glEnable(GL_BLEND); glEnable(GL_TEXTURE_2D); // activate pointer to vertex & texture array glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); My drawing code is being called by a NSTimer every 1/60 s. Here is the drawing code of my world object: - (void) draw:(NSRect)rect withTimedDelta:(double)d { GLint *t; glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, [_textureManager textureByName:@"blocks"]); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); for (int x=0; x<[_map getWidth] ; x++) { for (int y=0; y<[_map getHeight] ; y++) { GLint v[] = { 16*x ,16*y, 16*x+16,16*y, 16*x+16,16*y+16, 16*x ,16*y+16 }; t=[_textureManager getBlockWithNumber:[_map getBlockAtX:x andY:y]]; glVertexPointer(2, GL_INT, 0, v); glTexCoordPointer(2, GL_INT, 0, t); glDrawArrays(GL_QUADS, 0, 4); } } } (_textureManager is a Singelton only loading a texture once!) The object drawing codes is identical (except the nested loops) in terms of OpenGL calls: - (void) drawWithTimedDelta:(double)d { GLint *t; GLint v[] = { 16*xpos ,16*ypos, 16*xpos+16,16*ypos, 16*xpos+16,16*ypos+16, 16*xpos ,16*ypos+16 }; glBindTexture(GL_TEXTURE_2D, [_textureManager textureByName:_textureName]); t=[_textureManager getBlockWithNumber:12]; glVertexPointer(2, GL_INT, 0, v); glTexCoordPointer(2, GL_INT, 0, t); glDrawArrays(GL_QUADS, 0, 4); } As soon as my central drawing routine calls the two drawing methods the second call overlays the first one. i would expect the call to world.draw to draw the map and "stamp" the objects upon it. Debugging shows me, that the first call is performed correctly (world is being drawn), but the following call to all objects ONLY draws the objects, the rest of the scene is getting black. I think i need to blend the drawn textures, but i cant seem to figure out how. Any help is appreciated. Thanks PS: Here is the github link to the project. It may not be in sync of my post here, but for some more in-depth analysis it may help.

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  • Producing a smooth mesh from density cloud and marching cubes

    - by Wardy
    Based on my results from this question I decided to build myself a 3D noise map containing float values in place of my existing boolean point values. The effect I'm trying to produce is something like this, rather than typical rolling hills; which should explain the "missing cubes" in the image below. If I render my density map in normal "minecraft mode" (1 block per point in the density map) varying the size of the cube based on the value in my density map (floats in the range 0 to 1) I get something like this: I'm now happy that I can produce a density map for the marching cubes algorithm (which will need a little tweaking) but for some reason when I run it through my implementation it's not producing what I expect. My problem is that I'm getting something like the first image in this answer to my previous question, when I want to achieve the effect in the second image. Upon further investigation I can't see how marching cubes does the "move vertex along the edge" type logic (i.e. the difference between the two images on my previous link). I see that it does do some interpolation, but I'm not convinced I have the correct understanding of what I think it should do, because the code in question appears to give the same result regardless of whether I use boolean or float values. I took the code from here which is a C# implementation of marching cubes, but instead of using the MarchingCubesPrimitive I modified it to accept an object of type IDrawable, containing lists for the various collections (vertices, normals, UVs, indices), the logic was otherwise untouched. My understanding is that given a very low isovalue the accuracy level of the surface being rendered should increase, so in short "less 45 degree slows more rolling hills" type mesh output. However this isn't what I'm seeing. Have I missed something or is the implementation flawed and need to be fixed? EDIT: A little more detail on what I am seeing when I "marching cube" the data. Ok so firstly, ignore the fact that the meshes created by the chunks don't "connect" (i'll probably raise another question about this later). Then look at the shaping of the island, it's too ... square, from the voxels rendered as boxes you get the impression there's a clean soft gradual hill and yet from the image there are sharp falling edges even in the most central areas where the gradient in the first image looks the most smooth. The data is "regenerated" each time I run this so no 2 islands come out the same, and it's purely random so not based on noise, but still, how can it look so smooth in 1 image and so not smooth in the other?

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  • How can I convert a 2D bitmap (Used for terrain) to a 2D polygon mesh for collision?

    - by Megadanxzero
    So I'm making an artillery type game, sort of similar to Worms with all the usual stuff like destructible terrain etc... and while I could use per-pixel collision that doesn't give me collision normals or anything like that. Converting it all to a mesh would also mean I could use an existing physics library, which would be better than anything I can make by myself. I've seen people mention doing this by using Marching Squares to get contours in the bitmap, but I can't find anything which mentions how to turn these into a mesh (Unless it refers to a 3D mesh with contour lines defining different heights, which is NOT what I want). At the moment I can get a basic Marching Squares contour which looks something like this (Where the grid-like lines in the background would be the Marching Squares 'cells'): That needs to be interpolated to get a smoother, more accurate result but that's the general idea. I had a couple ideas for how to turn this into a mesh, but many of them wouldn't work in certain cases, and the one which I thought would work perfectly has turned out to be very slow and I've not even finished it yet! Ideally I'd like whatever I end up using to be fast enough to do every frame for cases such as rapidly-firing weapons, or digging tools. I'm thinking there must be some kind of existing algorithm/technique for turning something like this into a mesh, but I can't seem to find anything. I've looked at some things like Delaunay Triangulation, but as far as I can tell that won't correctly handle concave shapes like the above example, and also wouldn't account for holes within the terrain. I'll go through the technique I came up with for comparison and I guess I'll see if anyone has a better idea. First of all interpolate the Marching Squares contour lines, creating vertices from the line ends, and getting vertices where lines cross cell edges (Important). Then, for each cell containing vertices create polygons by using 2 vertices, and a cell corner as the 3rd vertex (Probably the closest corner). Do this for each cell and I think you should have a mesh which accurately represents the original bitmap (Though there will only be polygons at the edges of the bitmap, and large filled in areas in between will be empty). The only problem with this is that it involves lopping through every pixel once for the initial Marching Squares, then looping through every cell (image height + 1 x image width + 1) at least twice, which ends up being really slow for any decently sized image...

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  • Map and fill texture using PBO (OpenGL 3.3)

    - by NtscCobalt
    I'm learning OpenGL 3.3 trying to do the following (as it is done in D3D)... Create Texture of Width, Height, Pixel Format Map texture memory Loop write pixels Unmap texture memory Set Texture Render Right now though it renders as if the entire texture is black. I can't find a reliable source for information on how to do this though. Almost every tutorial I've found just uses glTexSubImage2D and passes a pointer to memory. Here is basically what my code does... (In this case it is generating an 1-byte Alpha Only texture but it is rendering it as the red channel for debugging) GLuint pixelBufferID; glGenBuffers(1, &pixelBufferID); glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pixelBufferID); glBufferData(GL_PIXEL_UNPACK_BUFFER, 512 * 512 * 1, nullptr, GL_STREAM_DRAW); glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0); GLuint textureID; glGenTextures(1, &textureID); glBindTexture(GL_TEXTURE_2D, textureID); glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, 512, 512, 0, GL_RED, GL_UNSIGNED_BYTE, nullptr); glBindTexture(GL_TEXTURE_2D, 0); glBindTexture(GL_TEXTURE_2D, textureID); glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pixelBufferID); void *Memory = glMapBuffer(GL_PIXEL_UNPACK_BUFFER, GL_WRITE_ONLY); // Memory copied here, I know this is valid because it is the same loop as in my working D3D version glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER); glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0); And then here is the render loop. // This chunk left in for completeness glUseProgram(glProgramId); glBindVertexArray(glVertexArrayId); glBindBuffer(GL_ARRAY_BUFFER, glVertexBufferId); glEnableVertexAttribArray(0); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 20, 0); glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 20, 12); GLuint transformLocationID = glGetUniformLocation(3, 'transform'); glUniformMatrix4fv(transformLocationID , 1, true, somematrix) // Not sure if this is all I need to do glBindTexture(GL_TEXTURE_2D, pTex->glTextureId); GLuint textureLocationID = glGetUniformLocation(glProgramId, "texture"); glUniform1i(textureLocationID, 0); glDrawArrays(GL_TRIANGLES, Offset*3, Triangles*3); Vertex Shader #version 330 core in vec3 Position; in vec2 TexCoords; out vec2 TexOut; uniform mat4 transform; void main() { TexOut = TexCoords; gl_Position = vec4(Position, 1.0) * transform; } Pixel Shader #version 330 core uniform sampler2D texture; in vec2 TexCoords; out vec4 fragColor; void main() { // Output color fragColor.r = texture2D(texture, TexCoords).r; fragColor.g = 0.0f; fragColor.b = 0.0f; fragColor.a = 1.0; }

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  • box2d resize bodies arround point

    - by philipp
    I have a compound object, consisting of a b2Body, vector-graphics and a list polygons which describe the b2body's shapes. This object has its own transformation matrix to centralize the storage of transformations. So far everything is working quiet fine, even scaling works, but not if i scale around a point. In the initialization phase of the object it is scaled around a point. This happens in this order: transform the main matrix transform the vector graphics and the polygons recreate the b2Body After this function ran, the shapes and all the graphics are exactly where they should be, BUT: after the first steps of the b2World the graphical stuff moves away from the body. When I ran the debugger I found out that the position of the body is 0/0 the red dot shows the center of scaling. the first image shows the basic setup and the second the final position of the graphics. This distance stays constant for the rest of the simulation. If I set the position via myBody.SetPosition( sx, sy ); the whole scenario just plays a bit more distant for the origin. Any Idea how to fix this? EDIT:: I came deeper down to the problem and it lies in the fact that i must not scale the transform matrix for the b2body shapes around the center, but set the b2body's position back to the point after scaling. But how can I calculate that point? EDIT 2 :: I came ever deeper down to it, even solved it, but this is a slow solution and i hope that there is somebody who understands what formula I need. assuming to have a set polygons relative to an origin as basis shapes for a b2body: scaling the whole object around a certain point is done in the following steps: i scale everything around the center except the polygons i create a clone of the polygons matrix i scale this clone around the point i calculate dx, dy as difference of clone.tx - original.tx and clone.ty - original.ty i scale the original polygon matrix NOT around the point i recreate the body i create the fixture i set the position of the body to dx and dy done! So what i an interested in is a formula for dx and dy without cloning matrices, scaling the clone around a point, getting dx and dy and finally scale the vertex matrix.

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  • OpenGL position from depth is wrong

    - by CoffeeandCode
    My engine is currently implemented using a deferred rendering technique, and today I decided to change it up a bit. First I was storing 5 textures as so: DEPTH24_STENCIL8 - Depth and stencil RGBA32F - Position RGBA10_A2 - Normals RGBA8 x 2 - Specular & Diffuse I decided to minimize it and reconstruct positions from the depth buffer. Trying to figure out what is wrong with my method currently has not been fun :/ Currently I get this: which changes whenever I move the camera... weird Vertex shader really simple #version 150 layout(location = 0) in vec3 position; layout(location = 1) in vec2 uv; out vec2 uv_f; void main(){ uv_f = uv; gl_Position = vec4(position, 1.0); } Fragment shader Where the fun (and not so fun) stuff happens #version 150 uniform sampler2D depth_tex; uniform sampler2D normal_tex; uniform sampler2D diffuse_tex; uniform sampler2D specular_tex; uniform mat4 inv_proj_mat; uniform vec2 nearz_farz; in vec2 uv_f; ... other uniforms and such ... layout(location = 3) out vec4 PostProcess; vec3 reconstruct_pos(){ float z = texture(depth_tex, uv_f).x; vec4 sPos = vec4(uv_f * 2.0 - 1.0, z, 1.0); sPos = inv_proj_mat * sPos; return (sPos.xyz / sPos.w); } void main(){ vec3 pos = reconstruct_pos(); vec3 normal = texture(normal_tex, uv_f).rgb; vec3 diffuse = texture(diffuse_tex, uv_f).rgb; vec4 specular = texture(specular_tex, uv_f); ... do lighting ... PostProcess = vec4(pos, 1.0); // Just for testing } Rendering code probably nothing wrong here, seeing as though it always worked before this->gbuffer->bind(); gl::Clear(gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT); gl::Enable(gl::DEPTH_TEST); gl::Enable(gl::CULL_FACE); ... bind geometry shader and draw models and shiz ... gl::Disable(gl::DEPTH_TEST); gl::Disable(gl::CULL_FACE); gl::Enable(gl::BLEND); ... bind textures and lighting shaders shown above then draw each light ... gl::BindFramebuffer(gl::FRAMEBUFFER, 0); gl::Clear(gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT); gl::Disable(gl::BLEND); ... bind screen shaders and draw quad with PostProcess texture ... Rinse_and_repeat(); // not actually a function ;) Why are my positions being output like they are?

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  • glGetActiveAttrib on Android NDK

    - by user408952
    In my code-base I need to link the vertex declarations from a mesh to the attributes of a shader. To do this I retrieve all the attribute names after linking the shader. I use the following code (with some added debug info since it's not really working): int shaders[] = { m_ps, m_vs }; if(linkProgram(shaders, 2)) { ASSERT(glIsProgram(m_program) == GL_TRUE, "program is invalid"); int attrCount = 0; GL_CHECKED(glGetProgramiv(m_program, GL_ACTIVE_ATTRIBUTES, &attrCount)); int maxAttrLength = 0; GL_CHECKED(glGetProgramiv(m_program, GL_ACTIVE_ATTRIBUTE_MAX_LENGTH, &maxAttrLength)); LOG_INFO("shader", "got %d attributes for '%s' (%d) (maxlen: %d)", attrCount, name, m_program, maxAttrLength); m_attrs.reserve(attrCount); GLsizei attrLength = -1; GLint attrSize = -1; GLenum attrType = 0; char tmp[256]; for(int i = 0; i < attrCount; i++) { tmp[0] = 0; GL_CHECKED(glGetActiveAttrib(m_program, GLuint(i), sizeof(tmp), &attrLength, &attrSize, &attrType, tmp)); LOG_INFO("shader", "%d: %d %d '%s'", i, attrLength, attrSize, tmp); m_attrs.append(String(tmp, attrLength)); } } GL_CHECKED is a macro that calls the function and calls glGetError() to see if something went wrong. This code works perfectly on Windows 7 using ANGLE and gives this this output: info:shader: got 2 attributes for 'static/simplecolor.glsl' (3) (maxlen: 11) info:shader: 0: 7 1 'a_Color' info:shader: 1: 10 1 'a_Position' But on my Nexus 7 (1st gen) I get the following (the errors are the output from the GL_CHECKED macro): I/testgame:shader(30865): got 2 attributes for 'static/simplecolor.glsl' (3) (maxlen: 11) E/testgame:gl(30865): 'glGetActiveAttrib(m_program, GLuint(i), sizeof(tmp), &attrLength, &attrSize, &attrType, tmp)' failed: INVALID_VALUE [jni/src/../../../../src/Game/Asset/ShaderAsset.cpp:50] I/testgame:shader(30865): 0: -1 -1 '' E/testgame:gl(30865): 'glGetActiveAttrib(m_program, GLuint(i), sizeof(tmp), &attrLength, &attrSize, &attrType, tmp)' failed: INVALID_VALUE [jni/src/../../../../src/Game/Asset/ShaderAsset.cpp:50] I/testgame:shader(30865): 1: -1 -1 '' I.e. the call to glGetActiveAttrib gives me an INVALID_VALUE. The opengl docs says this about the possible errors: GL_INVALID_VALUE is generated if program is not a value generated by OpenGL. This is not the case, I added an ASSERT to make sure glIsProgram(m_program) == GL_TRUE, and it doesn't trigger. GL_INVALID_OPERATION is generated if program is not a program object. Different error. GL_INVALID_VALUE is generated if index is greater than or equal to the number of active attribute variables in program. i is 0 and 1, and the number of active attribute variables are 2, so this isn't the case. GL_INVALID_VALUE is generated if bufSize is less than 0. Well, it's not zero, it's 256. Does anyone have an idea what's causing this? Am I just lucky that it works in ANGLE, or is the nvidia tegra driver wrong?

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  • Drawing lots of tiles with OpenGL, the modern way

    - by Nic
    I'm working on a small tile/sprite-based PC game with a team of people, and we're running into performance issues. The last time I used OpenGL was around 2004, so I've been teaching myself how to use the core profile, and I'm finding myself a little confused. I need to draw in the neighborhood of 250-750 48x48 tiles to the screen every frame, as well as maybe around 50 sprites. The tiles only change when a new level is loaded, and the sprites are changing all the time. Some of the tiles are made up of four 24x24 pieces, and most (but not all) of the sprites are the same size as the tiles. A lot of the tiles and sprites use alpha blending. Right now I'm doing all of this in immediate mode, which I know is a bad idea. All the same, when one of our team members tries to run it, he gets very bad frame rates (~20-30 fps), and it's much worse when there are more tiles, especially when a lot of those tiles are the kind that are cut into pieces. This all makes me think that the problem is the number of draw calls being made. I've thought of a few possible solutions to this, but I wanted to run them by some people who know what they're talking about so I don't waste my time on something stupid: TILES: When a level is loaded, draw all the tiles once into a frame buffer attached to a big honking texture, and just draw a big rectangle with that texture on it every frame. Put all the tiles into a static vertex buffer when the level is loaded, and draw them that way. I don't know if there's a way to draw objects with different textures with a single call to glDrawElements, or if this is even something I'd want to do. Maybe just put all the tiles into a big giant texture and use funny texture coordinates in the VBO? SPRITES: Draw each sprite with a separate call to glDrawElements. Use a dynamic VBO somehow. Same texture question as number 2 above. Point sprites? This is probably silly. Are any of these ideas sensible? Is there a good implementation somewhere I could look over?

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  • OpenGLES GLSL Shader attributes always bound to 0

    - by codemonkey
    So I have a very simple vertex shader as follows #version 120 attribute vec3 position; attribute vec3 inColor; uniform mat4 mvp; varying vec3 fragColor; void main(void){ fragColor = inColor; gl_Position = mvp * vec4(position, 1.0); } Which I load, as well as the fragment shader: #version 120 varying vec3 fragColor; void main(void) { gl_FragColor = vec4(fragColor,1.0); } Which I then load, compile, and link to my shader program. I check for link status using glGetProgramiv(shaderProgram, GL_LINK_STATUS, &shaderSuccess); which returns GL_TRUE so I think its ok. However, when I query the active attributes and uniforms using #ifdef DEBUG int totalAttributes = -1; glGetProgramiv(shaderProgram, GL_ACTIVE_ATTRIBUTES, &totalAttributes); for(int i=0; i<totalAttributes; ++i) { int name_len=-1, num=-1; GLenum type = GL_ZERO; char name[100]; glGetActiveAttrib(shaderProgram, GLuint(i), sizeof(name)-1, &name_len, &num, &type, name ); name[name_len] = 0; GLuint location = glGetAttribLocation(shaderProgram, name); fprintf(stderr, "Attribute %s is bound at %d\n", name, location); } int totalUniforms = -1; glGetProgramiv(shaderProgram, GL_ACTIVE_UNIFORMS, &totalUniforms); for(int i=0; i<totalUniforms; ++i) { int name_len=-1, num=-1; GLenum type = GL_ZERO; char name[100]; glGetActiveUniform(shaderProgram, GLuint(i), sizeof(name)-1, &name_len, &num, &type, name ); name[name_len] = 0; GLuint location = glGetUniformLocation(shaderProgram, name); fprintf(stderr, "Uniform %s is bound at %d\n", name, location); } #endif I get: Attribute inColor is bound at 0 Attribute position is bound at 1 Uniform mvp is bound at 0 Which leads to failure when trying to use the shader to render the objects. I have tried switching the order of declaration of position & inColor, but still, only position is bound with the other two giving 0 Can someone please explain why this is happening? Thanks

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  • How to export 3D models that consist of several parts (eg. turret on a tank)?

    - by Will
    What are the standard alternatives for the mechanics of attaching turrets and such to 3D models for use in-game? I don't mean the logic, but rather the graphics aspects. My naive approach is to extend the MD2-like format that I'm using (blender-exported using a script) to include a new set of properties for a mesh that: is anchored in another 'parent' mesh. The anchor is a point and normal in the parent mesh and a point and normal in the child mesh; these will always be colinear, giving the child rotation but not translation relative to the parent point. has a normal that is aligned with a 'target'. Classically this target is the enemy that is being engaged, but it might be some other vector e.g. 'the wind' (for sails and flags (and smoke, which is a particle system but the same principle applies)) or 'upwards' (e.g. so bodies of riders bend properly when riding a horse up an incline etc). that the anchor and target alignments have maximum and minimum and a speed coeff. there is game logic for multiple turrets and on a model and deciding which engages which enemy. 'primary' and 'secondary' or 'target0' ... 'targetN' or some such annotation will be there. So to illustrate, a classic tank would be made from three meshes; a main body mesh, a turret mesh that is anchored to the top of the main body so it can spin only horizontally and a barrel mesh that is anchored to the front of the turret and can only move vertically within some bounds. And there might be a forth flag mesh on top of the turret that is aligned with 'wind' where wind is a function the engine solves that merges environment's wind angle with angle the vehicle is travelling in an velocity, or something fancy. This gives each mesh one degree of freedom relative to its parent. Things with multiple degrees of freedom can be modelled by zero-vertex connecting meshes perhaps? This is where I think the approach I outlined begins to feel inelegant, yet perhaps its still a workable system? This is why I want to know how it is done in professional games ;) Are there better approaches? Are there formats that already include this information? Is this routine?

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  • Blender to 3ds max to cal3d format

    - by Kaliber64
    There are quite a few questions on cal3d but they are old and don't apply anymore. In Blender(must be 2.49a for python script to work!!!): I have a scene with 7 meshes, 1 armature, 10 bones. I tried going to one mesh to simplify it but doesn't change anything. I found a small blend file that was used for cal3d and it exported just fine. So I tried to copy it's setup with no success. EDIT*8/13/2012 In the last week here is what I have found so far. I made the mesh in the newest blender(2.62?) and exported it to import it in the old one(2.49a). Did an animation in the old one because importing new blend files to old blenders, its just said it would lose keyframe data and all was good. And then you get the last problem of it not exporting meshes. BUT I found that meshes made in the old one export regardless. I can't find any that won't export. So if I used the old blender to remake my model I could get it to export :) At this point I found a modified release of cal3d (because the most core model variable would not initiate as I made a really small test subject in old blender instead of remaking my big one which took 4 hours.) which fixes the morph objects and adds what cal3d left off with. Under their license they have to release the modification but it has no documentation so I have to figure it out on my own. Its mostly the same. But with this lib it came with a 3ds max exporter. My question now is how do I transfer armature and mesh information from blender to 3ds max in order to export into cal3d format. Every time I try the models are see through and small and there are no bones. The formats I have tried to import are .3ds .obj(mesh only) and COLLADA. In all of them the mesh is invisible and no bones. It says the default texture is on so I should be able to see it. All the vertices are present I found a vertex highlighter so I can see those. If any of this is confusing let me know so I can clear it up. Its late .<=sleep.

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  • How to optimise mesh data

    - by Wardy
    So i have some procedurally generated mesh data and i want to reduce it down to its minimum number of verts. In case it matters this is a unity project. Working on the basis of a simple example, lets assume a typical flat surface of points 2 by 3. The point / vertex at [1,1] is used in many triangles. I've generated mesh for a voxel type engine that adds verts to a list based on face visiblility and now I want to remove all the duplicates. Can anyone come up with an efficient way of doing this because what i have is sooo bad its not even funny (and i don't even think it's logically correct) ... private void Optimize() { Vector3 v; Vector3 v2; for (int i = 0; i < Vertices.Count; i++) { v = Vertices[i]; for (int j = i+1; j < Vertices.Count; j++) { v2 = Vertices[j]; if (v.x == v2.x && v.y == v2.y && v.z == v2.z) { for (int ind = 0; ind < Indices.Count; ind++) { if (Indices[ind] == j) { Indices[ind] = i; } else if (Indices[ind] > j && Indices[ind] > 0) Indices[ind]--; } Vertices.RemoveAt(j); Uvs.RemoveAt(j); Normals.RemoveAt(j); } } } } EDIT: Ok i managed to get this (code sample above updated) to render an "optimised" set of verts but the UV data is all wrong now, which would make sense because i'm basically just removing any UV Vector that represents a UV coord for a removed vert and not actually considering what I need to do to "fix the tri" so to speak. The code now seemingly does work but its quite time consuming, still looking to further optimise.

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  • GLSL per pixel lighting with custom light type

    - by Justin
    Ok, I am having a big problem here. I just got into GLSL yesterday, so the code will be terrible, I'm sure. Basically, I am attempting to make a light that can be passed into the fragment shader (for learning purposes). I have four input values: one for the position of the light, one for the color, one for the distance it can travel, and one for the intensity. I want to find the distance between the light and the fragment, then calculate the color from there. The code I have gives me a simply gorgeous ring of light that get's twisted and widened as the matrix is modified. I love the results, but it is not even close to what I am after. I want the light to be moved with all of the vertices, so it is always in the same place in relation to the objects. I can easily take it from there, but getting that to work seems to be impossible with my current structure. Can somebody give me a few pointers (pun not intended)? Vertex shader: attribute vec4 position; attribute vec4 color; attribute vec2 textureCoordinates; varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; void main() { vec4 ECposition = gl_ModelViewMatrix * gl_Vertex; vec3 tnorm = normalize(vec3 (gl_NormalMatrix * gl_Normal)); fposition = ftransform(); gl_Position = fposition; gl_TexCoord[0] = gl_MultiTexCoord0; fposition = ECposition; lightPosition = vec4(0.0, 0.0, 5.0, 0.0) * gl_ModelViewMatrix * gl_Vertex; lightDistance = 5.0; lightIntensity = 1.0; lightColor = vec4(0.2, 0.2, 0.2, 1.0); } Fragment shader: varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; uniform sampler2D texture; void main() { float l_distance = sqrt((gl_FragCoord.x * lightPosition.x) + (gl_FragCoord.y * lightPosition.y) + (gl_FragCoord.z * lightPosition.z)); float l_value = lightIntensity / (l_distance / lightDistance); vec4 l_color = vec4(l_value * lightColor.r, l_value * lightColor.g, l_value * lightColor.b, l_value * lightColor.a); vec4 color; color = texture2D(texture, gl_TexCoord[0].st); gl_FragColor = l_color * color; //gl_FragColor = fposition; }

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