获取 OpenGL 常用信息

void Context::getGLExtension()

{

const char* sVersion = (const char*)glGetString(GL_VERSION);

this->_version = std::string(sVersion);

const char* sShadingLanguageVersion =  (const char*)glGetString(GL_SHADING_LANGUAGE_VERSION);

this->_shadingLanguageVersion = std::string(sShadingLanguageVersion);

const char* sVendor =  (const char*)glGetString(GL_VENDOR);

this->_vendor = std::string(sVendor);

const char* sRenderer =  (const char*)glGetString(GL_RENDERER);

this->_renderer = std::string(sRenderer);

glGetIntegerv(GL_RED_BITS, &this->_redBits);

glGetIntegerv(GL_GREEN_BITS, &this->_greenBits);

glGetIntegerv(GL_BLUE_BITS, &this->_blueBits);

glGetIntegerv(GL_ALPHA_BITS, &this->_alphaBits);

glGetIntegerv(GL_DEPTH_BITS, &this->_depthBits);

glGetIntegerv(GL_STENCIL_BITS, &this->_stencilBits);

glGetIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS, &this->_maximumCombinedTextureImageUnits); // min: 8

glGetIntegerv(GL_MAX_CUBE_MAP_TEXTURE_SIZE, &this->_maximumCubeMapSize); // min: 16

glGetIntegerv(GL_MAX_FRAGMENT_UNIFORM_VECTORS, &this->_maximumFragmentUniformVectors); // min: 16

glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &this->_maximumTextureImageUnits); // min: 8

glGetIntegerv(GL_MAX_RENDERBUFFER_SIZE, &this->_maximumRenderbufferSize); // min: 1

glGetIntegerv(GL_MAX_TEXTURE_SIZE, &this->_maximumTextureSize); // min: 64

glGetIntegerv(GL_MAX_VARYING_VECTORS, &this->_maximumVaryingVectors); // min: 8

glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &this->_maximumVertexAttributes); // min: 8

glGetIntegerv(GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS, &this->_maximumVertexTextureImageUnits); // min: 0

glGetIntegerv(GL_MAX_VERTEX_UNIFORM_VECTORS, &this->_maximumVertexUniformVectors); // min: 128

glGetIntegerv(GL_ALIASED_LINE_WIDTH_RANGE, &this->_aliasedLineWidthRange); // must include 1

glGetIntegerv(GL_ALIASED_POINT_SIZE_RANGE, &this->_aliasedPointSizeRange); // must include 1

glGetIntegerv(GL_MAX_VIEWPORT_DIMS, this->_maximumViewportDimensions);

// Query and initialize extensions

this->_standardDerivatives = GL_OES_standard_derivatives;

this->_elementIndexUint = GL_OES_element_index_uint;

this->_depthTexture = GL_OES_depth_texture;

this->_textureFloat = GL_OES_texture_float;

this->_textureFilterAnisotropic = GL_EXT_texture_filter_anisotropic;

this->_maximumTextureFilterAnisotropy =  1.0;

this->_vertexArrayObject = GL_OES_vertex_array_object;

//this->_fragDepth = getExtension(gl, [‘EXT_frag_depth‘]);

//this._drawBuffers = getExtension(gl, [‘WEBGL_draw_buffers‘]);

//this->_maximumDrawBuffers = defined(this._drawBuffers) ? gl.getParameter(this._drawBuffers.MAX_DRAW_BUFFERS_WEBGL) : 1;

//this->_maximumColorAttachments = defined(this._drawBuffers) ? gl.getParameter(this._drawBuffers.MAX_COLOR_ATTACHMENTS_WEBGL) : 1; // min when supported: 4

GLfloat cc[4] = { 0.0, 0.0, 0.0, 0.0 };

glGetFloatv( GL_COLOR_CLEAR_VALUE, cc );

this->_clearColor = new Color(cc[0], cc[1], cc[2], cc[3]);

glGetIntegerv(GL_DEPTH_CLEAR_VALUE, &this->_clearDepth);

glGetIntegerv(GL_STENCIL_CLEAR_VALUE, &this->_clearStencil);

}