Re: [osg-users] passing uniforms to compute shader

[Mary-Ann Zorra]

Hi,

ok, maybe it is easier in that way.

Here are the uniforms of the compute shader:

Code:

struct PointLight {
vec4 position;
vec4 color;
vec4 paddingAndRadius;
};

// Shader storage buffer objects
layout(std140) uniform LightBuffer {
PointLight data[1024];
} ;
layout (binding = 0, r32f) writeonly uniform  image2D targetTex;

// Uniforms
uniform sampler2D depthMap;
uniform vec2 screenSize;
uniform int lightCount;
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;

// Shared values between all the threads in the group
shared uint minDepthInt;
shared uint maxDepthInt;
shared uint visibleLightCount;
shared vec4 frustumPlanes[6];
shared mat4 viewProjection;

#define TILE_SIZE 1
layout(local_size_x = TILE_SIZE, local_size_y = TILE_SIZE, local_size_z = 1) in;



And the uniforms of the fragment shader:

Code:


struct PointLight {
vec4 position;
vec4 color;
vec4 paddingAndRadius;
};

// Shader storage buffer objects
layout(std140) uniform LightBuffer{
PointLight data[1024];
} ;

uniform sampler2D VisibleLightIndicesBuffer;
uniform int numberOfTilesX;
uniform int totalLightCount;



And how I bind them to the compute shader: 

Code:

computeShaderStateset->addUniform(new osg::Uniform("depthMap",2));
computeShaderStateset->setTextureAttributeAndModes(2,depthTexture, 
osg::StateAttribute::ON);
computeShaderStateset->addUniform(new osg::Uniform("screenSize", 
osg::Vec2(windowWidth, windowHeight)));
computeShaderStateset->addUniform(new osg::Uniform("lightCount", (int) 
lights->size()));
computeShaderStateset->getOrCreateUniform("projectionMatrix", 
osg::Uniform::FLOAT_MAT4)->set(projectionMatrix);
computeShaderStateset->getOrCreateUniform("viewMatrix", 
osg::Uniform::FLOAT_MAT4)->set(viewMatrix);

//indices
osg::ref_ptr indexTexture = new osg::Texture2D;
indexTexture->setTextureSize(1024, 1024);
indexTexture->setFilter(osg::Texture::MIN_FILTER, osg::Texture2D::LINEAR);
indexTexture->setFilter(osg::Texture::MAG_FILTER, osg::Texture2D::LINEAR);
indexTexture->setInternalFormat(GL_R32F);
indexTexture->setSourceFormat(GL_RED);
indexTexture->setSourceType(GL_FLOAT);
indexTexture->bindToImageUnit(0, osg::Texture::WRITE_ONLY);
computeShaderStateset->addUniform(new osg::Uniform("targetTex", (int)0));
computeShaderStateset->setTextureAttributeAndModes(0, indexTexture.get());

//lights
std::vector byteLights = convertLightVector(lights);
osg::ByteArray* bytes = new osg::ByteArray([0], 
[sizeof(byteLights) * sizeof(char) * byteLights.size()]);
osg::UniformBufferObject* uboLights = new osg::UniformBufferObject;
uboLights->setUsage(GL_STATIC_DRAW);
uboLights->setDataVariance(osg::Object::STATIC);
bytes->setBufferObject(uboLights);
osg::UniformBufferBinding* ubbLights = new osg::UniformBufferBinding(10, 
uboLights, 0, bytes->size());
computeShaderStateset->setAttributeAndModes(ubbLights, 
osg::StateAttribute::ON);
computeShaderProgram->addBindUniformBlock("LightBuffer", 10);



And to the fragment shader:


Code:
 //Uniforms
mStateset->addUniform(new osg::Uniform("numberOfTilesX", (int) 
((windowWidth + (windowWidth % 16)) / 16) ));
mStateset->addUniform(new osg::Uniform("totalLightCount", (int) 
lights->size()));
//indices
mStateset->addUniform(new osg::Uniform("VisibleLightIndicesBuffer",1));
mStateset->setTextureAttributeAndModes(1,indices, osg::StateAttribute::ON | 
osg::StateAttribute::OVERRIDE);

 //lights
std::vector byteLights = convertLightVector(lights);
osg::ByteArray* bytes = new osg::ByteArray([0], 
[sizeof(byteLights) * sizeof(char) * byteLights.size()]);
osg::UniformBufferObject* uboLights = new osg::UniformBufferObject;
uboLights->setUsage(GL_STATIC_DRAW);
uboLights->setDataVariance(osg::Object::STATIC);
bytes->setBufferObject(uboLights);
osg::UniformBufferBinding* ubbLights = new osg::UniformBufferBinding(0, 
uboLights, 0, bytes->size());
mStateset->setAttributeAndModes(ubbLights, osg::StateAttribute::ON);
lightShader->addBindUniformBlock("LightBuffer", 0);



The part how I pass the lights is the same, but in the case of compute shader 
nothing happens, no light arrives. All uniforms have a reasonable value in the 
fragment shader, but they are always 0 (or empty), except the image2D targetTex 
object,  in the compute shader. I checked all variables in the code, and I 
know, that their value is ok, so the mistake is surely in binding, but I don't 
know where.

Thank you for any help!

Cheers,
Mary-Ann

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Re: [osg-users] passing uniforms to compute shader

[Gianni Ambrosio]

Well, you could provide the code you use so that someone can find the error.

Cheers,
Gianni

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[osg-users] passing uniforms to compute shader

[Mary-Ann Zorra]

Hi everyone, 

I am trying to write a functional compute shader, but the uniforms dont't want 
to work. 
I have a compute and a usual shader program currently. The compute shader has 
to write a texture, which can be read by the usual shader. This part works 
fine. But I would like to pass some (custom) uniforms (lights, amount of the 
light sources, projection/view matrix etc.). I use the same method by the two 
shaders, , but the data seems to arrive only by the usual shader program. 
I thought something could be wrong with the compute shader, but the texture 
data is there, so the communication is working. Should I pass the uniforms in 
an other way, when I have to send data to a compute shader? I can't figure it 
out, where is the mistake... 

Thanks a lot  :)
Mary-Ann

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