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  • cocos2d/OpenGL multitexturing problem

    - by Gajoo
    I've got a simple shader to test multitextureing the problem is both samplers are using same image as their reference. the shader code is basically just this : vec4 mid = texture2D(u_texture,v_texCoord); float g = texture2D(u_guide,v_guideCoord); gl_FragColor = vec4(g , mid.g,0,1); and this is how I'm calling draw function : int last_State; glGetIntegerv(GL_ACTIVE_TEXTURE, &last_State); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, getTexture()->getName()); glActiveTexture(GL_TEXTURE1); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, mGuideTexture->getName()); ccGLEnableVertexAttribs( kCCVertexAttribFlag_TexCoords |kCCVertexAttribFlag_Position); glVertexAttribPointer(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, vertices); glVertexAttribPointer(kCCVertexAttrib_TexCoords, 2, GL_FLOAT, GL_FALSE, 0, texCoord); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); glDisable(GL_TEXTURE_2D); I've already check mGuideTexture->getName() and getTexture()->getName() are returning correct textures. but looking at the result I can tell, both samplers are reading from getTexture()->getName(). here are some screen shots showing what is happening : The image rendered Using above codes The image rendered when I change textures passed to samples I'm expecting to see green objects from the first picture with red objects hanging from the top.

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  • Adding a decal using multitexturing on an iPhone

    - by Axis
    I'm trying to overlay one image on top of another onto a simple quad. I set my bottom image as texture unit 0, and then my top image (which has a variable alpha) as texture unit 1. Unit 2 has mode GL_DECAL, which means the bottom texture should show up when the alpha is 0, and the top texture should show when the alpha is 1. But, only the top texture shows up and the bottom one doesn't appear at all. It's just white where the bottom texture should show through. glGetError() doesn't report any problems. Any help is appreciated. Thanks! glVertexPointer(3, GL_FLOAT, 0, boxVertices); glEnableClientState(GL_VERTEX_ARRAY); glClientActiveTexture(GL_TEXTURE0); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glTexCoordPointer(2, GL_FLOAT, 0, boxTextureCoords); glClientActiveTexture(GL_TEXTURE1); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glTexCoordPointer(2, GL_FLOAT, 0, boxTextureCoords); glClientActiveTexture(GL_TEXTURE0); glEnable(GL_TEXTURE_2D); glClientActiveTexture(GL_TEXTURE1); glEnable(GL_TEXTURE_2D); glClientActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, one.texture); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glClientActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, two.texture); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL); glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

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  • How can I read from multiple textures in an OpenGL ES 2 shader?

    - by Peyman Tahghighi
    How can I enable more than one texture in OpenGL ES 2 so that I can sample from all of them in my shader? For example, I'm trying to read from two different textures in my shader for the player's car. This is how I'm currently dealing with the texture for my car: glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, this->texture2DObj); glUniform1i(1, 0); glBindBuffer(GL_ARRAY_BUFFER, this->vertexBuffer); glEnableVertexAttribArray(0); int offset = 0; glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, this->vertexBufferSize,(const void *)offset); offset += 3 * sizeof(GLfloat); glEnableVertexAttribArray(1); glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, this->vertexBufferSize, (const void*)offset); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->indexBuffer); glDrawElements(GL_TRIANGLES, this->indexBufferSize, GL_UNSIGNED_SHORT, 0); glDisableVertexAttribArray(0); glDisableVertexAttribArray(1);

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  • Very slow direct3D texture sampling

    - by __dominic
    Hi, So I'm writing a small game using Direct3D 9 and I'm using multitexturing for the terrain. All I'm doing is sampling 3 textures and a blend map and getting the overall color from the three textures based on the color channels from the blend map. Anyway, I am getting a massive frame rate drop when I sample more than 1 texture, I'm going from 120+ fps to just under 50. This is the HLSL code responsible for the slow down: float3 ground = tex2D(GroundTex, multiTex).rgb; float3 stone = tex2D(StoneTex, multiTex).rgb; float3 grass = tex2D(GrassTex, multiTex).rgb; float3 blend = tex2D(BlendMapTex, blendMap).rgb; Am I doing it wrong ? If anyone has any info or tips about texture sampling or anything, that would be nice. Thanks.

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  • iPhone openGLES performance tuning

    - by genesys
    Hey there! I'm trying now for quite a while to optimize the framerate of my game without really making progress. I'm running on the newest iPhone SDK and have a iPhone 3G 3.1.2 device. I invoke arround 150 drawcalls, rendering about 1900 Triangles in total (all objects are textured using two texturelayers and multitexturing. most textures come from the same textureAtlasTexture stored in pvrtc 2bpp compressed texture). This renders on my phone at arround 30 fps, which appears to me to be way too low for only 1900 triangles. I tried many things to optimize the performance, including batching together the objects, transforming the vertices on the CPU and rendering them in a single drawcall. this yelds 8 drawcalls (as oposed to 150 drawcalls), but performance is about the same (fps drop to arround 26fps) I'm using 32byte vertices stored in an interleaved array (12bytes position, 12bytes normals, 8bytes uv). I'm rendering triangleLists and the vertices are ordered in TriStrip order. I did some profiling but I don't really know how to interprete it. instruments-sampling using Instruments and Sampling yelds this result: http://neo.cycovery.com/instruments_sampling.gif telling me that a lot of time is spent in "mach_msg_trap". I googled for it and it seems this function is called in order to wait for some other things. But wait for what?? instruments-openGL instruments with the openGL module yelds this result: http://neo.cycovery.com/intstruments_openglES_debug.gif but here i have really no idea what those numbers are telling me shark profiling: profiling with shark didn't tell me much either: http://neo.cycovery.com/shark_profile_release.gif the largest number is 10%, spent by DrawTriangles - and the whole rest is spent in very small percentage functions Can anyone tell me what else I could do in order to figure out the bottleneck and could help me to interprete those profiling information? Thanks a lot!

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  • Need guidelines for optimizing WebGL performance by minimizing shader changes

    - by brainjam
    I'm trying to get an idea of the practicality of WebGL for rendering large architectural interior scenes, consisting of 100K's of triangles. These triangles are distributed over many objects, and there are many materials in the scene. On the other hand, there are no moving parts. And the materials tend to be fairly simple, mostly based on texture maps. There is a lot of texture map sharing .. for example all the chairs in scene will share a common map. There is also some multitexturing - up to three textures overlaid in a material. I've been doing a little experimentation and reading, and gather that frequently switching materials during a rendering pass will slow things down. For example, a scene with 200K triangles will have significant performance differences, depending on whether there are 10 or 1000 objects, assuming that each time an object is displayed a new material is set up. So it seems that if performance is important the scene should be sorted by materials so as to minimize material switching. What I'm looking for is guidelines on how to think of the overhead of various state changes, and where do I get the biggest bang for the buck. For example, what are the relative performance costs of, say, gl.useProgram(), gl.uniformMatrix4fv(), gl.drawElements() should I try to write ubershaders to minimize shader switching? should I try to aggregate geometry to minimize the number of gl.drawElements() calls I realize that mileage may vary depending on browser, OS, and graphics hardware. And I'm also not looking for heroic measures. Just some guidelines from people who have already had some experience in making scenes fast. I'll add that while I've had some experience with fixed-pipeline OpenGL programming in the past, I'm rather new to the WebGL/OpenGL ES 2.0 way of doing things.

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