// setTextureUnit activates a texture unit func setTextureUnit(textureunit int) error { if textureunit < 0 || textureunit >= len(gl_state.boundTextures) { return fmt.Errorf("Invalid texture unit index (%v).", textureunit) } if textureunit != gl_state.curTextureUnit { gl.ActiveTexture(gl.Enum(gl.TEXTURE0 + uint32(textureunit))) } gl_state.curTextureUnit = textureunit return nil }
// InitContext will initiate the opengl context with a viewport in the size of // w x h. This is generally called from the game loop and wont generally need to // be called unless you are rolling your own game loop. func InitContext(w, h int32) { if gl_state.initialized { return } // Okay, setup OpenGL. gl.ContextWatcher.OnMakeCurrent(nil) //Get system info opengl_version = gl.GetString(gl.VERSION) opengl_vendor = gl.GetString(gl.VENDOR) gl_state.defaultFBO = gl.GetBoundFramebuffer() gl.GetIntegerv(gl.VIEWPORT, gl_state.viewport) // And the current scissor - but we need to compensate for GL scissors // starting at the bottom left instead of top left. gl.GetIntegerv(gl.SCISSOR_BOX, states.back().scissorBox) states.back().scissorBox[1] = gl_state.viewport[3] - (states.back().scissorBox[1] + states.back().scissorBox[3]) initMaxValues() //check shim code glcolor := []float32{1.0, 1.0, 1.0, 1.0} gl.VertexAttrib4fv(attrib_color, glcolor) gl.VertexAttrib4fv(attrib_constantcolor, glcolor) useVertexAttribArrays(0) // Enable blending gl.Enable(gl.BLEND) SetBlendMode(BLENDMODE_ALPHA) // Auto-generated mipmaps should be the best quality possible gl.Hint(gl.GENERATE_MIPMAP_HINT, gl.NICEST) // Make sure antialiasing works when set elsewhere enableMultisample() //check shim code // Set pixel row alignment gl.PixelStorei(gl.UNPACK_ALIGNMENT, 1) //default matricies gl_state.projectionStack = matstack.NewMatStack() gl_state.viewStack = matstack.NewMatStack() //stacks are initialized with ident matricies on top SetViewportSize(w, h) SetBackgroundColor(0, 0, 0, 255) gl_state.boundTextures = make([]gl.Texture, maxTextureUnits) curgltextureunit := gl.GetInteger(gl.ACTIVE_TEXTURE) gl_state.curTextureUnit = int(curgltextureunit - gl.TEXTURE0) // Retrieve currently bound textures for each texture unit. for i := 0; i < len(gl_state.boundTextures); i++ { gl.ActiveTexture(gl.Enum(gl.TEXTURE0 + uint32(i))) gl_state.boundTextures[i] = gl.Texture{Value: uint32(gl.GetInteger(gl.TEXTURE_BINDING_2D))} } gl.ActiveTexture(gl.Enum(curgltextureunit)) createDefaultTexture() setTextureUnit(0) // We always need a default shader. defaultShader = NewShader() gl_state.initialized = true loadAllVolatile() //have to set this after loadallvolatile() so we are sure the default shader is loaded SetShader(nil) }