[OGRE 1.x] Uniform buffer shader support

[WilliamLewww]

Uniform Buffer Shader Support

Related Issue #24

Summary

Currently only INT and FLOAT uniforms are encoded with ShaderParam. The new uniform buffers take advantage of OGRE's following method:

void Ogre::GpuProgramParameters::setNamedConstant(const String& name, const int* val, size_t count, size_t multiple = 4)

Any uniform buffer with a type size of 4 bytes will be available to update and use in a shader program.

uniform float testFloat;
uniform int testInt;
uniform float testFloatBuffer[6];
uniform int testIntBuffer[5];
uniform vec3 testVector3;
uniform vec4 testVector4;
uniform mat4 textMatrix4;

Test it

Build and run the example custom_shaders_uniforms

To-do

• Remove raw pointers for host uniform buffers

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)

[ahcorde]

Some style issues

[iche033]

nice demo. I have a few style suggestions.

ogre works fine but I get a crash with ogre2 though

[WilliamLewww]

nice demo. I have a few style suggestions.

ogre works fine but I get a crash with ogre2 though

I only worked with the ogre1 files so far because the original custom_shaders example crashes with ogre2 for me. I'm going to dig around the files to see if I can fix the problem or if the problem only exists on my machine.

[iche033]

I'm going to dig around the files to see if I can fix the problem or if the problem only exists on my machine.

ok thanks. If it's not trivial to fix, we can ticket an issue first. But I think we should at least print an error msg and have the demo exit gracefully.

[WilliamLewww]

Implementing uniform buffers in OGRE2 requires a little more work than expected.

Currently only the PBS Hlms is implemented but custom shaders require the LowLevel Hlms implementation.

https://github.com/ignitionrobotics/ign-rendering/blob/a2c172a234ba3ce8b66223fda6197c8778322f57/ogre2/src/Ogre2Material.cc#L531-L535

https://github.com/ignitionrobotics/ign-rendering/blob/a2c172a234ba3ce8b66223fda6197c8778322f57/ogre2/include/ignition/rendering/ogre2/Ogre2Material.hh#L223-L224

I will see if I can implement the two other Hlms (Unlit and LowLevel), but they would probably need their own separate pull request.

[ahcorde]

The Windows PR is yet a draft but I think it makes sense to include here at least the right variables and includes.

[iche033]

There are some code check errors. Can you run sh tools/code_check.sh from the ign-rendering dir and and address the issues related to your changes?