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  • Use depth bias for shadows in deferred shading

    - by cubrman
    We are building a deferred shading engine and we have a problem with shadows. To add shadows we use two maps: the first one stores the depth of the scene captured by the player's camera and the second one stores the depth of the scene captured by the light's camera. We then ran a shader that analyzes the two maps and outputs the third one with the ready shadow areas for the current frame. The problem we face is a classic one: Self-Shadowing: A standard way to solve this is to use the slope-scale depth bias and depth offsets, however as we are doing things in a deferred way we cannot employ this algorithm. Any attempts to set depth bias when capturing light's view depth produced no or unsatisfying results. So here is my question: MSDN article has a convoluted explanation of the slope-scale: bias = (m × SlopeScaleDepthBias) + DepthBias Where m is the maximum depth slope of the triangle being rendered, defined as: m = max( abs(delta z / delta x), abs(delta z / delta y) ) Could you explain how I can implement this algorithm manually in a shader? Maybe there are better ways to fix this problem for deferred shadows?

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  • Generating Normal map from a Image with a given Albedo map

    - by snape
    I am working on a research problem part of which involves generating normal map from a given image of a rusted object. I searched the internet for techniques to achieve the above and apparently crazybump is mentioned a lot. I tried it but it didn't produce the desirable effects. Also I am looking for a method which draws inspiration from an existing research paper not some closed source software. I turned my attention to the technique described in the this paper. Results from this technique are satisfactory for normal objects because of bias in the training data but it doesn't work very well in the case of rusted objects. After this I focussed my attention on generating Albedo map (the above problem would become more solvable if Albedo map is obtained). Fortunately I am able to generate pretty good albedo maps for images of rusted objects. I used this paper's approach to generate Albedo maps. Now I want to know a good technique to get Normal map given an image and it's corresponding Albedo map. To give you an idea of what kind of images I am working with I am attaching a sample. Links to research material would be really appreciated. Thanks!

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  • How can I find the right UV coordinates for interpolating a bezier curve?

    - by ssb
    I'll let this picture do the talking. I'm trying to create a mesh from a bezier curve and then add a texture to it. The problem here is that the interpolation points along the curve do not increase linearly, so points farther from the control point (near the endpoints) stretch and those in the bend contract, causing the texture to be uneven across the curve, which can be problematic when using a pattern like stripes on a road. How can I determine how far along the curve the vertices actually are so I can give a proper UV coordinate? EDIT: Allow me to clarify that I'm not talking about the trapezoidal distortion of the roads. That I know is normal and I'm not concerned about. I've updated the image to show more clearly where my concerns are. Interpolating over the curve I get 10 segments, but each of these 10 segments is not spaced at an equal point along the curve, so I have to account for this in assigning UV data to vertices or else the road texture will stretch/shrink depending on how far apart vertices are at that particular part of the curve.

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  • Is there any difference between storing textures and baked lighting for environment meshes?

    - by Ben Hymers
    I assume that when texturing environments, one or several textures will be used, and the UVs of the environment geometry will likely overlap on these textures, so that e.g. a tiling brick texture can be used by many parts of the environment, rather than UV unwrapping the entire thing, and having several areas of the texture be identical. If my assumption is wrong, please let me know! Now, when thinking about baking lighting, clearly this can't be done the same way - lighting in general will be unique to every face so the environment must be UV unwrapped without overlap, and lighting must be baked onto unique areas of one or several textures, to give each surface its own texture space to store its lighting. My questions are: Have I got this wrong? If so, how? Isn't baking lighting going to use a lot of texture space? Will the geometry need two UV sets, one used for the colour/normal texture and one for the lighting texture? Anything else you'd like to add? :)

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  • Normal maps red in OpenGL?

    - by KaiserJohaan
    I am using Assimp to import 3d models, and FreeImage to parse textures. The problem I am having is that the normal maps are actually red rather than blue when I try to render them as normal diffuse textures. http://i42.tinypic.com/289ing3.png When I open the images in a image-viewing program they do indeed show up as blue. Heres when I create the texture; OpenGLTexture::OpenGLTexture(const std::vector<uint8_t>& textureData, uint32_t textureWidth, uint32_t textureHeight, TextureType textureType, Logger& logger) : mLogger(logger), mTextureID(gNextTextureID++), mTextureType(textureType) { glGenTextures(1, &mTexture); CHECK_GL_ERROR(mLogger); glBindTexture(GL_TEXTURE_2D, mTexture); CHECK_GL_ERROR(mLogger); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, textureWidth, textureHeight, 0, glTextureFormat, GL_UNSIGNED_BYTE, &textureData[0]); CHECK_GL_ERROR(mLogger); glGenerateMipmap(GL_TEXTURE_2D); CHECK_GL_ERROR(mLogger); glBindTexture(GL_TEXTURE_2D, 0); CHECK_GL_ERROR(mLogger); } Here is my fragment shader. You can see I just commented out the normal-map parsing and treated the normal map texture as the diffuse texture to display it and illustrate the problem. As for the rest of the code it interacts as expected with the diffuse textures so I dont see a obvious problem there. "#version 330 \n \ \n \ layout(std140) uniform; \n \ \n \ const int MAX_LIGHTS = 8; \n \ \n \ struct Light \n \ { \n \ vec4 mLightColor; \n \ vec4 mLightPosition; \n \ vec4 mLightDirection; \n \ \n \ int mLightType; \n \ float mLightIntensity; \n \ float mLightRadius; \n \ float mMaxDistance; \n \ }; \n \ \n \ uniform UnifLighting \n \ { \n \ vec4 mGamma; \n \ vec3 mViewDirection; \n \ int mNumLights; \n \ \n \ Light mLights[MAX_LIGHTS]; \n \ } Lighting; \n \ \n \ uniform UnifMaterial \n \ { \n \ vec4 mDiffuseColor; \n \ vec4 mAmbientColor; \n \ vec4 mSpecularColor; \n \ vec4 mEmissiveColor; \n \ \n \ bool mHasDiffuseTexture; \n \ bool mHasNormalTexture; \n \ bool mLightingEnabled; \n \ float mSpecularShininess; \n \ } Material; \n \ \n \ uniform sampler2D unifDiffuseTexture; \n \ uniform sampler2D unifNormalTexture; \n \ \n \ in vec3 frag_position; \n \ in vec3 frag_normal; \n \ in vec2 frag_texcoord; \n \ in vec3 frag_tangent; \n \ in vec3 frag_bitangent; \n \ \n \ out vec4 finalColor; " " \n \ \n \ void CalcGaussianSpecular(in vec3 dirToLight, in vec3 normal, out float gaussianTerm) \n \ { \n \ vec3 viewDirection = normalize(Lighting.mViewDirection); \n \ vec3 halfAngle = normalize(dirToLight + viewDirection); \n \ \n \ float angleNormalHalf = acos(dot(halfAngle, normalize(normal))); \n \ float exponent = angleNormalHalf / Material.mSpecularShininess; \n \ exponent = -(exponent * exponent); \n \ \n \ gaussianTerm = exp(exponent); \n \ } \n \ \n \ vec4 CalculateLighting(in Light light, in vec4 diffuseTexture, in vec3 normal) \n \ { \n \ if (light.mLightType == 1) // point light \n \ { \n \ vec3 positionDiff = light.mLightPosition.xyz - frag_position; \n \ float dist = max(length(positionDiff) - light.mLightRadius, 0); \n \ \n \ float attenuation = 1 / ((dist/light.mLightRadius + 1) * (dist/light.mLightRadius + 1)); \n \ attenuation = max((attenuation - light.mMaxDistance) / (1 - light.mMaxDistance), 0); \n \ \n \ vec3 dirToLight = normalize(positionDiff); \n \ float angleNormal = clamp(dot(normalize(normal), dirToLight), 0, 1); \n \ \n \ float gaussianTerm = 0.0; \n \ if (angleNormal > 0.0) \n \ CalcGaussianSpecular(dirToLight, normal, gaussianTerm); \n \ \n \ return diffuseTexture * (attenuation * angleNormal * Material.mDiffuseColor * light.mLightIntensity * light.mLightColor) + \n \ (attenuation * gaussianTerm * Material.mSpecularColor * light.mLightIntensity * light.mLightColor); \n \ } \n \ else if (light.mLightType == 2) // directional light \n \ { \n \ vec3 dirToLight = normalize(light.mLightDirection.xyz); \n \ float angleNormal = clamp(dot(normalize(normal), dirToLight), 0, 1); \n \ \n \ float gaussianTerm = 0.0; \n \ if (angleNormal > 0.0) \n \ CalcGaussianSpecular(dirToLight, normal, gaussianTerm); \n \ \n \ return diffuseTexture * (angleNormal * Material.mDiffuseColor * light.mLightIntensity * light.mLightColor) + \n \ (gaussianTerm * Material.mSpecularColor * light.mLightIntensity * light.mLightColor); \n \ } \n \ else if (light.mLightType == 4) // ambient light \n \ return diffuseTexture * Material.mAmbientColor * light.mLightIntensity * light.mLightColor; \n \ else \n \ return vec4(0.0); \n \ } \n \ \n \ void main() \n \ { \n \ vec4 diffuseTexture = vec4(1.0); \n \ if (Material.mHasDiffuseTexture) \n \ diffuseTexture = texture(unifDiffuseTexture, frag_texcoord); \n \ \n \ vec3 normal = frag_normal; \n \ if (Material.mHasNormalTexture) \n \ { \n \ diffuseTexture = vec4(normalize(texture(unifNormalTexture, frag_texcoord).xyz * 2.0 - 1.0), 1.0); \n \ // vec3 normalTangentSpace = normalize(texture(unifNormalTexture, frag_texcoord).xyz * 2.0 - 1.0); \n \ //mat3 tangentToWorldSpace = mat3(normalize(frag_tangent), normalize(frag_bitangent), normalize(frag_normal)); \n \ \n \ // normal = tangentToWorldSpace * normalTangentSpace; \n \ } \n \ \n \ if (Material.mLightingEnabled) \n \ { \n \ vec4 accumLighting = vec4(0.0); \n \ \n \ for (int lightIndex = 0; lightIndex < Lighting.mNumLights; lightIndex++) \n \ accumLighting += Material.mEmissiveColor * diffuseTexture + \n \ CalculateLighting(Lighting.mLights[lightIndex], diffuseTexture, normal); \n \ \n \ finalColor = pow(accumLighting, Lighting.mGamma); \n \ } \n \ else { \n \ finalColor = pow(diffuseTexture, Lighting.mGamma); \n \ } \n \ } \n"; Why is this? does normal-map textures need some sort of special treatment in opengl?

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  • Understanding normal maps on terrain

    - by JohnB
    I'm having trouble understanding some of the math behind normal map textures even though I've got it to work using borrowed code, I want to understand it. I have a terrain based on a heightmap. I'm generating a mesh of triangles at load time and rendering that mesh. Now for each vertex I need to calculate a normal, a tangent, and a bitangent. My understanding is as follows, have I got this right? normal is a unit vector facing outwards from the surface of the triangle. For a vertex I take the average of the normals of the triangles using that vertex. tangent is a unit vector in the direction of the 'u' coordinates of the texture map. As my texture u,v coordinates follow the x and y coordinates of the terrain, then my understanding is that this vector is simply the vector along the surface in the x direction. So should be able to calculate this as simply the difference between vertices in the x direction to get a vector, (and normalize it). bitangent is a unit vector in the direction of the 'v' coordinates of the texture map. As my texture u,v coordinates follow the x and y coordinates of the terrain, then my understanding is that this vector is simply the vector along the surface in the y direction. So should be able to calculate this as simply the difference between vertices in the y direction to get a vector, (and normalize it). However the code I have borrowed seems much more complicated than this and takes into account the actual values of u, and v at each vertex which I don't understand the need for as they increase in exactly the same direction as x, and y. I implemented what I thought from above, and it simply doesn't work, the normals are clearly not working for lighting. Have I misunderstood something? Or can someone explain to me the physical meaning of the tangent and bitangent vectors when applied to a mesh generated from a hightmap like this, when u and v texture coordinates map along the x and y directions. Thanks for any help understanding this.

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  • Compute directional light frustum from view furstum points and light direction

    - by Fabian
    I'm working on a friends engine project and my task is to construct a new frustum from the light direction that overlaps the view frustum and possible shadow casters. The project already has a function that creates a frustum for this but its way to big and includes way to many casters (shadows) which can't be seen in the view frustum. Now the only parameter of this function are the normalized light direction vector and a view class which lets me extract the 8 view frustum points in world space. I don't have any additional infos about the scene. I have read some of the related Questions here but non seem to fit very well to my problem as they often just point to cascaded shadow maps. Sadly i can't use DX or openGl functions directly because this engine has a dedicated math library. From what i've read so far the steps are: Transform view frustum points into light space and find min/max x and y values (or sometimes minima and maxima of all three axis) and create a AABB using the min/max vectors. But what comes after this step? How do i transform this new AABB back to world space? What i've done so far: CVector3 Points[8], MinLight = CVector3(FLT_MAX), MaxLight = CVector3(FLT_MAX); for(int i = 0; i<8;++i){ Points[i] = Points[i] * WorldToShadowMapMatrix; MinLight = Math::Min(Points[i],MinLight); MaxLight = Math::Max(Points[i],MaxLight); } AABox box(MinLight,MaxLight); I don't think this is the right way to do it. The near plain probably has to extend into the direction of the light source to include potentional shadow casters. I've read the Microsoft article about cascaded shadow maps http://msdn.microsoft.com/en-us/library/windows/desktop/ee416307%28v=vs.85%29.aspx which also includes some sample code. But they seem to use the scenes AABB to determine the near and far plane which I can't since i cant access this information from the funtion I'm working in. Could you guys please link some example code which shows the calculation of such frustum? Thanks in advance! Additional questio: is there a way to construct a WorldToFrustum matrix that represents the above transformation?

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  • Drawing a textured triangle with CPU instead of GPU

    - by Jenko
    I understand the benefits of GPU rendering and such, but for a certain limited application I need to render textured triangles purely using CPU. I've built a 3D engine capable of object handling, transform, projection, culling and the likes ... now all I need is a little code snippet that draws a single textured triangle onto a bitmap... any language accepted! Inputs: Texture bitmap, Triangle U/V/W coords, Triangle X/Y screen coords Output: The textured triangle drawn at the given screen coords I've currently been using a platform function to draw triangles to screen, but I'm looking to handle it myself to speeden up the process.

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  • Why aren't tangent space normal maps completely blue?

    - by seahorse
    Why aren't normal maps just blue? I would think that normal maps should be predominantly blue in color because the Z component of the normal is represented by blue. Normals point out of the surface in the Z direction so we should see blue as the predominant colour since the Z component is dominant. By definition tangent space is perpendicular to the surface. At any point we should have the normal always pointing in the Z (blue direction) with no X (red direction) or Y (green direction). Thus the normal map (since it is a "normal map") should have the colour of the normals which is just blue (R = x = 0, G = y = 0, B = z = 1) with no shades in between. But normal maps are not so, and they have gradients of shades in them. Why is this so?

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  • Normals vs Normal maps

    - by KaiserJohaan
    I am using Assimp asset importer (http://assimp.sourceforge.net/lib_html/index.html) to parse 3d models. So far, I've simply pulled out the normal vectors which are defined for each vertex in my meshes. Yet I have also found various tutorials on normal maps... As I understand it for normal maps, the normal vectors are stored in each texel of a normal map, and you pull these out of the normal texture in the shader. Why is there two ways to get the normals, which one is considered best-practice and why?

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  • Why does multiplying texture coordinates scale the texture?

    - by manning18
    I'm having trouble visualizing this geometrically - why is it that multiplying the U,V coordinates of a texture coordinate has the effect of scaling that texture by that factor? eg if you scaled the texture coordinates by a factor of 3 ..then doesn't this mean that if you had texture coordinates 0,1 and 0,2 ...you'd be sampling 0,3 and 0,6 in the U,V texture space of 0..1? How does that make it bigger eg HLSL: tex2D(textureSampler, TexCoords*3) Integers make it smaller, decimals make it bigger I mean I understand intuitively if you added to the U,V coordinates, as that is simply an offset into the sampling range, but what's the case with multiplication? I have a feeling when someone explains this to me I'm going to be feeling mighty stupid

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  • Center directional light shadow to the cameras eye

    - by Caesar
    I'm currently drawing my directional light shadow using this view and projection: XMFLOAT3 dir((float)pitch, (float)yaw, (float)roll); XMFLOAT3 center(0.0f, 0.0f, 0.0f); XMVECTOR lightDir = XMLoadFloat3(&dir); XMVECTOR lightPos = radius * lightDir; XMVECTOR targetPos = XMLoadFloat3(&center); XMVECTOR up = XMVectorSet(0.0f, 1.0f, 0.0f, 0.0f); XMMATRIX V = XMMatrixLookAtLH(lightPos, targetPos, up); // This is the view // Transform bounding sphere to light space. XMFLOAT3 sphereCenterLS; XMStoreFloat3(&sphereCenterLS, XMVector3TransformCoord(targetPos, V)); // Ortho frustum in light space encloses scene. float l = sphereCenterLS.x - radius; float b = sphereCenterLS.y - radius; float n = sphereCenterLS.z - radius; float r = sphereCenterLS.x + radius; float t = sphereCenterLS.y + radius; float f = sphereCenterLS.z + radius; XMMATRIX P = XMMatrixOrthographicOffCenterLH(l, r, b, t, n, f); // This is the projection Which works prefect if the center of my scene is at 0.0, 0.0, 0.0. What I would like to do is move the center of the scene relative to the cameras position. How can I do that?

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  • How do you calculate UVW coordinates?

    - by Jenko
    I'm working on a 3d engine and I'm calculating UVT coordinates, where U and V represent pixels on the texture measured in 0-1, and T is: T = perspective / Z But I'm trying to use this perspective-correct triangle rasteriser, which requires a W, per vertex. How do I calculate the W for each vertex for the drawPerspectiveTexturedPolygon() function? Hint: The code comments refer to W as the "homogenous coordinate" ... does that mean anything?

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  • CSM shadow errors when models are split

    - by KaiserJohaan
    I'm getting closer to fixing CSM, but there seems to be one more issue at hand. At certain angles, the models will be caught/split between two shadow map cascades, like below. first depth split second depth split - here you can see the model is caught between the splits How does one fix this? Increase the overlapping boundaries between the splits? Or is the frustrum erronous? CameraFrustrum CalculateCameraFrustrum(const float fovDegrees, const float aspectRatio, const float minDist, const float maxDist, const Mat4& cameraViewMatrix, Mat4& outFrustrumMat) { CameraFrustrum ret = { Vec4(1.0f, -1.0f, 0.0f, 1.0f), Vec4(1.0f, 1.0f, 0.0f, 1.0f), Vec4(-1.0f, 1.0f, 0.0f, 1.0f), Vec4(-1.0f, -1.0f, 0.0f, 1.0f), Vec4(1.0f, -1.0f, 1.0f, 1.0f), Vec4(1.0f, 1.0f, 1.0f, 1.0f), Vec4(-1.0f, 1.0f, 1.0f, 1.0f), Vec4(-1.0f, -1.0f, 1.0f, 1.0f), }; const Mat4 perspectiveMatrix = PerspectiveMatrixFov(fovDegrees, aspectRatio, minDist, maxDist); const Mat4 invMVP = glm::inverse(perspectiveMatrix * cameraViewMatrix); outFrustrumMat = invMVP; for (Vec4& corner : ret) { corner = invMVP * corner; corner /= corner.w; } return ret; } Mat4 CreateDirLightVPMatrix(const CameraFrustrum& cameraFrustrum, const Vec3& lightDir) { Mat4 lightViewMatrix = glm::lookAt(Vec3(0.0f), -glm::normalize(lightDir), Vec3(0.0f, -1.0f, 0.0f)); Vec4 transf = lightViewMatrix * cameraFrustrum[0]; float maxZ = transf.z, minZ = transf.z; float maxX = transf.x, minX = transf.x; float maxY = transf.y, minY = transf.y; for (uint32_t i = 1; i < 8; i++) { transf = lightViewMatrix * cameraFrustrum[i]; if (transf.z > maxZ) maxZ = transf.z; if (transf.z < minZ) minZ = transf.z; if (transf.x > maxX) maxX = transf.x; if (transf.x < minX) minX = transf.x; if (transf.y > maxY) maxY = transf.y; if (transf.y < minY) minY = transf.y; } Mat4 viewMatrix(lightViewMatrix); viewMatrix[3][0] = -(minX + maxX) * 0.5f; viewMatrix[3][1] = -(minY + maxY) * 0.5f; viewMatrix[3][2] = -(minZ + maxZ) * 0.5f; viewMatrix[0][3] = 0.0f; viewMatrix[1][3] = 0.0f; viewMatrix[2][3] = 0.0f; viewMatrix[3][3] = 1.0f; Vec3 halfExtents((maxX - minX) * 0.5, (maxY - minY) * 0.5, (maxZ - minZ) * 0.5); return OrthographicMatrix(-halfExtents.x, halfExtents.x, halfExtents.y, -halfExtents.y, halfExtents.z, -halfExtents.z) * viewMatrix; }

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  • Where can I find free or buy "next-gen" 3D Assets?

    - by Valmond
    Usually I buy 3D Assets from sites like turbosquid.com or similar. My problem is that I have lately implemented glow, normal maps, specular (and specular power) maps and reflection maps and I can't find any models that use those techniques. So where can I find / buy "next gen" assets (at least models/items with a normal map)? I have checked for similar posts but those I found are about either free only or 2D or 'ordinary' 3D so I hope this is not a duplicate.

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  • PCF shadow shader math causing artifacts

    - by user2971069
    For a while now I used PCSS for my shadow technique of choice until I discovered a type of percentage closer filtering. This method creates really smooth shadows and with hopes of improving performance, with only a fraction of texture samples, I tried to implement PCF into my shader. This is the relevant code: float c0, c1, c2, c3; float f = blurFactor; float2 coord = ProjectedTexCoords; if (receiverDistance - tex2D(lightSampler, coord + float2(0, 0)).x > 0.0007) c0 = 1; if (receiverDistance - tex2D(lightSampler, coord + float2(f, 0)).x > 0.0007) c1 = 1; if (receiverDistance - tex2D(lightSampler, coord + float2(0, f)).x > 0.0007) c2 = 1; if (receiverDistance - tex2D(lightSampler, coord + float2(f, f)).x > 0.0007) c3 = 1; coord = (coord % f) / f; return 1 - (c0 * (1 - coord.x) * (1 - coord.y) + c1 * coord.x * (1 - coord.y) + c2 * (1 - coord.x) * coord.y + c3 * coord.x * coord.y); This is a very basic implementation. blurFactor is initialized with 1 / LightTextureSize. So the if statements fetch the occlusion values for the four adjacent texels. I now want to weight each value based on the actual position of the texture coordinate. If it's near the bottom-right pixel, that occlusion value should be preferred. The weighting itself is done with a simple bilinear interpolation function, however this function takes a 2d vector in the range [0..1] so I have to convert my texture coordinate to get the distance from my first pixel to the second one in range [0..1]. For that I used the mod operator to get it into [0..f] range and then divided by f. This code makes sense to me, and for specific blurFactors it works, producing really smooth one pixel wide shadows, but not for all blurFactors. Initially blurFactor is (1 / LightTextureSize) to sample the 4 adjacent texels. I now want to increase the blurFactor by factor x to get a smooth interpolation across maybe 4 or so pixels. But that is when weird artifacts show up. Here is an image: Using a 1x on blurFactor produces a good result, 0.5 is as expected not so smooth. 2x however doesn't work at all. I found that only a factor of 1/2^n produces an good result, every other factor produces artifacts. I'm pretty sure the error lies here: coord = (coord % f) / f; Maybe the modulo is not calculated correctly? I have no idea how to fix that. Is it even possible for pixel that are further than 1 pixel away?

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  • Normal map applied as diffuse textures looks wrong

    - by KaiserJohaan
    Diffuse textures works fine, but I am having problem with normal maps, so I thought I'd tried to apply the normal maps as the diffuse map in my fragment shader so I could see everything is OK. I comment-out my normal map code and just set the diffuse map to the normal map and I get this: http://postimg.org/image/j9gudjl7r/ Looks like a smurf! This is the actual normal map of the main body: http://postimg.org/image/sbkyr6fg9/ Here is my fragment shader, notice I commented out normal map code so I could debug the normal map as a diffuse texture "#version 330 \n \ \n \ layout(std140) uniform; \n \ \n \ const int MAX_LIGHTS = 8; \n \ \n \ struct Light \n \ { \n \ vec4 mLightColor; \n \ vec4 mLightPosition; \n \ vec4 mLightDirection; \n \ \n \ int mLightType; \n \ float mLightIntensity; \n \ float mLightRadius; \n \ float mMaxDistance; \n \ }; \n \ \n \ uniform UnifLighting \n \ { \n \ vec4 mGamma; \n \ vec3 mViewDirection; \n \ int mNumLights; \n \ \n \ Light mLights[MAX_LIGHTS]; \n \ } Lighting; \n \ \n \ uniform UnifMaterial \n \ { \n \ vec4 mDiffuseColor; \n \ vec4 mAmbientColor; \n \ vec4 mSpecularColor; \n \ vec4 mEmissiveColor; \n \ \n \ bool mHasDiffuseTexture; \n \ bool mHasNormalTexture; \n \ bool mLightingEnabled; \n \ float mSpecularShininess; \n \ } Material; \n \ \n \ uniform sampler2D unifDiffuseTexture; \n \ uniform sampler2D unifNormalTexture; \n \ \n \ in vec3 frag_position; \n \ in vec3 frag_normal; \n \ in vec2 frag_texcoord; \n \ in vec3 frag_tangent; \n \ in vec3 frag_bitangent; \n \ \n \ out vec4 finalColor; " " \n \ \n \ void CalcGaussianSpecular(in vec3 dirToLight, in vec3 normal, out float gaussianTerm) \n \ { \n \ vec3 viewDirection = normalize(Lighting.mViewDirection); \n \ vec3 halfAngle = normalize(dirToLight + viewDirection); \n \ \n \ float angleNormalHalf = acos(dot(halfAngle, normalize(normal))); \n \ float exponent = angleNormalHalf / Material.mSpecularShininess; \n \ exponent = -(exponent * exponent); \n \ \n \ gaussianTerm = exp(exponent); \n \ } \n \ \n \ vec4 CalculateLighting(in Light light, in vec4 diffuseTexture, in vec3 normal) \n \ { \n \ if (light.mLightType == 1) // point light \n \ { \n \ vec3 positionDiff = light.mLightPosition.xyz - frag_position; \n \ float dist = max(length(positionDiff) - light.mLightRadius, 0); \n \ \n \ float attenuation = 1 / ((dist/light.mLightRadius + 1) * (dist/light.mLightRadius + 1)); \n \ attenuation = max((attenuation - light.mMaxDistance) / (1 - light.mMaxDistance), 0); \n \ \n \ vec3 dirToLight = normalize(positionDiff); \n \ float angleNormal = clamp(dot(normalize(normal), dirToLight), 0, 1); \n \ \n \ float gaussianTerm = 0.0; \n \ if (angleNormal > 0.0) \n \ CalcGaussianSpecular(dirToLight, normal, gaussianTerm); \n \ \n \ return diffuseTexture * (attenuation * angleNormal * Material.mDiffuseColor * light.mLightIntensity * light.mLightColor) + \n \ (attenuation * gaussianTerm * Material.mSpecularColor * light.mLightIntensity * light.mLightColor); \n \ } \n \ else if (light.mLightType == 2) // directional light \n \ { \n \ vec3 dirToLight = normalize(light.mLightDirection.xyz); \n \ float angleNormal = clamp(dot(normalize(normal), dirToLight), 0, 1); \n \ \n \ float gaussianTerm = 0.0; \n \ if (angleNormal > 0.0) \n \ CalcGaussianSpecular(dirToLight, normal, gaussianTerm); \n \ \n \ return diffuseTexture * (angleNormal * Material.mDiffuseColor * light.mLightIntensity * light.mLightColor) + \n \ (gaussianTerm * Material.mSpecularColor * light.mLightIntensity * light.mLightColor); \n \ } \n \ else if (light.mLightType == 4) // ambient light \n \ return diffuseTexture * Material.mAmbientColor * light.mLightIntensity * light.mLightColor; \n \ else \n \ return vec4(0.0); \n \ } \n \ \n \ void main() \n \ { \n \ vec4 diffuseTexture = vec4(1.0); \n \ if (Material.mHasDiffuseTexture) \n \ diffuseTexture = texture(unifDiffuseTexture, frag_texcoord); \n \ \n \ vec3 normal = frag_normal; \n \ if (Material.mHasNormalTexture) \n \ { \n \ diffuseTexture = vec4(normalize(texture(unifNormalTexture, frag_texcoord).xyz * 2.0 - 1.0), 1.0); \n \ // vec3 normalTangentSpace = normalize(texture(unifNormalTexture, frag_texcoord).xyz * 2.0 - 1.0); \n \ //mat3 tangentToWorldSpace = mat3(normalize(frag_tangent), normalize(frag_bitangent), normalize(frag_normal)); \n \ \n \ // normal = tangentToWorldSpace * normalTangentSpace; \n \ } \n \ \n \ if (Material.mLightingEnabled) \n \ { \n \ vec4 accumLighting = vec4(0.0); \n \ \n \ for (int lightIndex = 0; lightIndex < Lighting.mNumLights; lightIndex++) \n \ accumLighting += Material.mEmissiveColor * diffuseTexture + \n \ CalculateLighting(Lighting.mLights[lightIndex], diffuseTexture, normal); \n \ \n \ finalColor = pow(accumLighting, Lighting.mGamma); \n \ } \n \ else { \n \ finalColor = pow(diffuseTexture, Lighting.mGamma); \n \ } \n \ } \n"; Here is my wrapper around a texture OpenGLTexture::OpenGLTexture(const std::vector<uint8_t>& textureData, uint32_t textureWidth, uint32_t textureHeight, TextureFormat textureFormat, TextureType textureType, Logger& logger) : mLogger(logger), mTextureID(gNextTextureID++), mTextureType(textureType) { glGenTextures(1, &mTexture); CHECK_GL_ERROR(mLogger); glBindTexture(GL_TEXTURE_2D, mTexture); CHECK_GL_ERROR(mLogger); GLint glTextureFormat = (textureFormat == TextureFormat::TEXTURE_FORMAT_RGB ? GL_RGB : textureFormat == TextureFormat::TEXTURE_FORMAT_RGBA ? GL_RGBA : GL_RED); glTexImage2D(GL_TEXTURE_2D, 0, glTextureFormat, textureWidth, textureHeight, 0, glTextureFormat, GL_UNSIGNED_BYTE, &textureData[0]); CHECK_GL_ERROR(mLogger); glGenerateMipmap(GL_TEXTURE_2D); CHECK_GL_ERROR(mLogger); glBindTexture(GL_TEXTURE_2D, 0); CHECK_GL_ERROR(mLogger); } OpenGLTexture::~OpenGLTexture() { glDeleteBuffers(1, &mTexture); CHECK_GL_ERROR(mLogger); } And here is the sampler I create which is shared between Diffuse and normal textures // texture sampler setup glGenSamplers(1, &mTextureSampler); CHECK_GL_ERROR(mLogger); glSamplerParameteri(mTextureSampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR); CHECK_GL_ERROR(mLogger); glSamplerParameteri(mTextureSampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST); CHECK_GL_ERROR(mLogger); glSamplerParameteri(mTextureSampler, GL_TEXTURE_WRAP_S, GL_REPEAT); CHECK_GL_ERROR(mLogger); glSamplerParameteri(mTextureSampler, GL_TEXTURE_WRAP_T, GL_REPEAT); CHECK_GL_ERROR(mLogger); glSamplerParameterf(mTextureSampler, GL_TEXTURE_MAX_ANISOTROPY_EXT, mCurrentAnisotropy); CHECK_GL_ERROR(mLogger); glUniform1i(glGetUniformLocation(mDefaultProgram.GetHandle(), "unifDiffuseTexture"), OpenGLTexture::TEXTURE_UNIT_DIFFUSE); CHECK_GL_ERROR(mLogger); glUniform1i(glGetUniformLocation(mDefaultProgram.GetHandle(), "unifNormalTexture"), OpenGLTexture::TEXTURE_UNIT_NORMAL); CHECK_GL_ERROR(mLogger); glBindSampler(OpenGLTexture::TEXTURE_UNIT_DIFFUSE, mTextureSampler); CHECK_GL_ERROR(mLogger); glBindSampler(OpenGLTexture::TEXTURE_UNIT_NORMAL, mTextureSampler); CHECK_GL_ERROR(mLogger); SetAnisotropicFiltering(mCurrentAnisotropy); The diffuse textures looks like they should, but the normal looks so wierd. Why is this?

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  • Why don't Normal maps in tangent space have a single blue color?

    - by seahorse
    Normal maps are predominantly blue in color because the z component maps to Blue and since normals point out of the surface in the z direction we see Blue as the predominant component. If the above is true then why are normal maps just of one color i.e. blue and they should not be having any other shades(not even shades of blue) Since by definition tangent space is perpendicular to normal at any point we should have the normal always pointing in the Z (Blue direction) with no X(Red component) and Y(Green component). Thus the normal map(since it is a "normal map") should have had color of normals which is just the Blue(Z =Blue compoennt = 1, R=0, G=0) and the normal map should have been of only Blue color with no shades in between. But even then normal maps are not so, and they have gradients of shades in them, why is this so?

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  • samplerCubeShadow and texture offset

    - by Irbis
    I use sampler2DShadow when accessing a single shadow map. I create PCF in this way: result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(-1,-1)); result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(-1,1)); result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(1,1)); result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(1,-1)); result = result * 0.25; For a cube map I use samplerCubeShadow: result = texture(ShadowCubeSampler, vec4(normalize(position), depth)); How to adopt above PCF when accessing a cube map ?

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  • How can I prevent seams from showing up on objects using lower mipmap levels?

    - by Shivan Dragon
    Disclaimer: kindly right click on the images and open them separately so that they're at full size, as there are fine details which don't show up otherwise. Thank you. I made a simple Blender model, it's a cylinder with the top cap removed: I've exported the UVs: Then imported them into Photoshop, and painted the inner area in yellow and the outer area in red. I made sure I cover well the UV lines: I then save the image and load it as texture on the model in Blender. Actually, I just reload it as the image where the UVs are exported, and change the viewport view mode to textured. When I look at the mesh up-close, there's yellow everywhere, everything seems fine: However, if I start zooming out, I start seeing red (literally and metaphorically) where the texture edges are: And the more I zoom, the more I see it: Same thing happends in Unity, though the effect seems less pronounced. Up close is fine and yellow: Zoom out and you see red at the seams: Now, obviously, for this simple example a workaround is to spread the yellow well outside the UV margins, and its fine from all distances. However this is an issue when you try making a complex texture that should tile seamlessly at the edges. In this situation I either make a few lines of pixels overlap (in which case it looks bad from upclose and ok from far away), or I leave them seamless and then I have those seams when seeing it from far away. So my question is, is there something I'm missing, or some extra thing I must do to have my texture look seamless from all distances?

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  • OpenGL lighting with dynamic geometry

    - by Tank
    I'm currently thinking hard about how to implement lighting in my game. The geometry is quite dynamic (fixed 3D grid with custom geometry in each cell) and needs some light to get more depth and in general look nicer. A scene in my game always contains sunlight and local light sources like lamps (point lights). One can move underground, so sunlight must be able to illuminate as far as it can get. Here's a render of a typical situation: The lamp is positioned behind the wall to the top, and in the hollow cube there's a hole in the back, so that light can shine through. (I don't want soft shadows, this is just for illustration) While spending the whole day searching through Google, I stumbled on some keywords like deferred rendering, forward rendering, ambient occlusion, screen space ambient occlusion etc. Some articles/tutorials even refer to "normal shading", but to be honest I don't really have an idea to even do simple shading. OpenGL of course has a fixed lighting pipeline with 8 possible light sources. However they just illuminate all vertices without checking for occluding geometry. I'd be very thankful if someone could give me some pointers into the right direction. I don't need complete solutions or similar, just good sources with information understandable for someone with nearly no lighting experience (preferably with OpenGL).

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  • Exporting UV coords from Blender

    - by Soapy
    So I have searched on google and various other websites but I've not found an answer. The only ones I did find did not work. So my question is how do I get UV coords from blender (2.63)? Currently I'm writing my own custom file exporter, and so far have managed to export vertices and their normals. Is there a way to export the UV coords? N.B. I'm currently try to figure it out using a simple cube that is unwrapped and has a texture applied to it.

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  • HLSL 5 interpolation issues

    - by metredigm
    I'm having issues with the depth components of my shadowmapping shaders. The shadow map rendering shader is fine, and works very well. The world rendering shader is more problematic. The only value which seems to definitely be off is the pixel's position from the light's perspective, which I pass in parallel to the position. struct Pixel { float4 position : SV_Position; float4 light_pos : TEXCOORD2; float3 normal : NORMAL; float2 texcoord : TEXCOORD; }; The reason that I used the semantic 'TEXCOORD2' on the light's pixel position is because I believe that the problem lies with Direct3D's interpolation of values between shaders, and I started trying random semantics and also forcing linear and noperspective interpolations. In the world rendering shader, I observed in the pixel shader that the Z value of light_pos was always extremely close to, but less than the W value. This resulted in a depth result of 0.999 or similar for every pixel. Here is the vertex shader code : struct Vertex { float3 position : POSITION; float3 normal : NORMAL; float2 texcoord : TEXCOORD; }; struct Pixel { float4 position : SV_Position; float4 light_pos : TEXCOORD2; float3 normal : NORMAL; float2 texcoord : TEXCOORD; }; cbuffer Camera : register (b0) { matrix world; matrix view; matrix projection; }; cbuffer Light : register (b1) { matrix light_world; matrix light_view; matrix light_projection; }; Pixel RenderVertexShader(Vertex input) { Pixel output; output.position = mul(float4(input.position, 1.0f), world); output.position = mul(output.position, view); output.position = mul(output.position, projection); output.world_pos = mul(float4(input.position, 1.0f), world); output.world_pos = mul(output.world_pos, light_view); output.world_pos = mul(output.world_pos, light_projection); output.texcoord = input.texcoord; output.normal = input.normal; return output; } I suspect interpolation to be the culprit, as I used the camera matrices in place of the light matrices in the vertex shader, and had the same problem. The problem is evident as both of the same vectors were passed to a pixel from the VS, but only one of them showed a change in the PS. I have already thoroughly debugged the matrices' validity, the cbuffers' validity, and the multiplicative validity. I'm very stumped and have been trying to solve this for quite some time. Misc info : The light projection matrix and the camera projection matrix are the same, generated from D3DXMatrixPerspectiveFovLH(), with an FOV of 60.0f * 3.141f / 180.0f, a near clipping plane of 0.1f, and a far clipping plane of 1000.0f. Any ideas on what is happening? (This is a repost from my question on Stack Overflow)

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  • Sampling Heightmap Edges for Normal map

    - by pl12
    I use a Sobel filter to generate normal maps from procedural height maps. The heightmaps are 258x258 pixels. I scale my texture coordinates like so: texCoord = (texCoord * (256/258)) + (1/258) Yet even with this I am left with the following problem: As you can see the edges of the normal map still proves to be problematic. Putting the texture wrap mode to "clamp" also proved no help. EDIT: The Sobel Filter function by sampling the 8 surrounding pixels around a given pixel so that a derivative can be calculated in order to find the "normal" of the given pixel. The texture coordinates are instanced once per quad (for the quadtree that makes up the world) and are created as follows (it is quite possible that the problem results from the way I scale and offset the texCoords as seen above): Java: for(int i = 0; i<vertices.length; i++){ Vector2f coord = new Vector2f((vertices[i].x)/(worldSize), (vertices[i].z)/( worldSize)); texCoords[i] = coord; } the quad used for input here rests on the X0Z plane. 'worldSize' is the diameter of the planet. No negative texCoords are seen as the quad used for input for this method is not centered around the origin. Is there something I am missing here? Thanks.

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  • Bad texture on model with different GPU

    - by Pacha
    I have some kind of distortion on the texture of my 3D model. It works perfectly well on an AMD GPU, but when testing on a integrated Intel HD graphics card it has a weird issue. I don't have a problem with the rest of my entities as they are not scaled. The models with the problems are scaled, as my engine supports different sizes for the platforms. I am using Ogre3D as rendering engine, and GLSL as shader language. Vertex shader: #version 120 varying vec2 UV; void main() { UV = gl_MultiTexCoord0; gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; } Fragment shader: #version 120 varying vec2 UV; uniform sampler2D diffuseMap; void main(void) { gl_FragColor = texture(diffuseMap, UV); } Screenshot (the error is on the right and left side, the top and bottom part are rendered perfectly well):

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