GR Graphics gets graphics

This post describes the first steps and the main Shader class for the GR Graphics library, OpenGL binding.



The Win32 bindings for the OpenGl version of the renderers, contexts and shaders were created.

The main plugin-based  shader class was created (hlslModularProgram).

The class exposes the all- important Activate, Init, Reshape, Render methods.
Init takes in a templatized object that, depending on the definition, contains different fields to activate and deactivate features.

Starting supported features were:

• usesVertexPositions (denotes that the vertex shader will have Position defined as an input parameter) -> exposes vertexPosition_AttributeName as a configuration parameter, which then the plugin will use to retrieve the relevant attribute location where a mesh's Position will be uploaded
• usesVertexNormals (denotes that the vertex shader will have Position defined as an input parameter) -> exposes vertexNormal_AttributeName as a configuration parameter, which then the plugin will use to retrieve the relevant attribute location where a mesh's Normals will be uploaded
• usesTexUvs
• usesLights
• usesMaterials

Since these were enough to get going, the rest would have to wait a bit.

After some necessary work of actually implementing the Plugins that were using the above attributes, the first, simplistic, per-vertex lighted sphere appeared on the screen. No screenshots for that I'm afraid :)

An example of the way the class is instantiated follows

//The template parameters activate and deactivate the features
        typedef grg::xlslModularProgram < _myApi,
                true, true, true, true, true, false, false > shaderType;
        auto shader = new shaderType(Context());
        shader->createProgram("data\\shaders\\PerFragment_vs.glsl", "data\\shaders\\PerFragment_BlinnPhong_fs.glsl");

//The configuration object's fields change depending on the template parameters defined in the shader
        auto config = shader->getConfigurationObject();

        config.core_EntityManager = &entityManager;

        config.light_CoordinateSpace = grg::CoordinateSpaces::WORLD_SPACE;
        config.light_UniformBlockName = "Lights";

        config.material_UniformName = "material";

        config.matrix_Camera = &camera;
        config.matrix_UniformBlockName = "Matrices";

        config.vertexPos_AttributeName = "position";
        config.vertexNormal_AttributeName = "normal";

        shader->init(config);
        grg::xlslTechnique<_myApi> temp = grg::xlslTechnique<_myApi>();
        temp.push_back(shader);
        shaderManager.addTechnique(temp);