shader

I'm quite a bit confused about framebuffers. What I want to do is using a framebuffer with multiple textures attached, fill every texture and then use a shader to combine (blend) all textures to create a new output. Sounds easy? yeah that's what I thought too, but I don't understand it. How can I pass the currently binded texture to a shader? What you need is to put the texture in a specific slot, then use a sampler to read from it. In your app: GLuint frameBuffer; glGenFramebuffersEXT(1, &frameBuffer); //Create a frame buffer glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, frameBuffer); //Bind it so

EXT_occlusion_query_boolean is new with OS5.0, it looks to me like not a single person on the entire internet has posted about these new extensions nor used this code.... so here they are set up properly...which is not documented anywhere as far as i can tell... you can imagine how they would go in your code from this little sudo code here: import UIKit/UIKit.h import GLKit/GLKit.h import "GLProgram.h" GLuint testBox,hasBeenTested,theParams; //... glGenQueriesEXT(1, &testBox); glBeginQueryEXT(GL_ANY_SAMPLES_PASSED_EXT, testBox); //... draw an object ....... glEndQueryEXT(GL_ANY_SAMPLES_PASSED

I have a shader where I want to move half of the vertices in the vertex shader. I'm trying to decide the best way to do this from a performance standpoint, because we're dealing with well over 100,000 verts, so speed is critical. I've looked at 3 different methods: (pseudo-code, but enough to give you the idea. The <complex formula> I can't give out, but I can say that it involves a sin() function, as well as a function call (just returns a number, but still a function call), as well as a bunch of basic arithmetic on floating point numbers). if (y < 0.5) { x += <complex formula>; } This has

When I pass non max values into texture buffer, while rendering it draws geometry with colors at max values. I found this issue while using glTexBuffer() API. E.g. Let’s assume my texture data is GLubyte, when I pass any value less than 255, then the color is same as that of drawn with 255, instead of mixture of black and that color. I tried on AMD and nvidia card, but the results are same. Can you tell me where could be going wrong? I am copying my code here: Vert shader: in vec2 a_position; uniform float offset_x; void main() { gl_Position = vec4(a_position.x + offset_x, a_position.y, 1.0, 1

I'm trying to find the most efficient way of handling multi-texturing in OpenGL ES2 on iOS. By 'efficient' I mean the fastest rendering even on older iOS devices (iPhone 4 and up) - but also balancing convenience. I've considered (and tried) several different methods. But have run into a couple of problems and questions. Method 1 - My base and normal values are rgb with NO ALPHA. For these objects I don't need transparency. My emission and specular information are each only one channel. To reduce texture2D() calls I figured I could store the emission as the alpha channel of the base, and the

I have an extremely simple PNG texture: a grey circle with a transparent background. I use it as a uniform map for a THREE.ShaderMaterial : var uniforms = THREE.UniformsUtils.merge( [basicShader.uniforms] ); uniforms['map'].value = THREE.ImageUtils.loadTexture( "img/particle.png" ); uniforms['size'].value = 100; uniforms['opacity'].value = 0.5; uniforms['psColor'].value = new THREE.Color( 0xffffff ); Here is my fragment shader (just part of it): gl_FragColor = vec4( psColor, vOpacity ); gl_FragColor = gl_FragColor * texture2D( map,vec2( gl_PointCoord.x, 1.0 - gl_PointCoord.y ) ); gl_FragColor