lighttroupe/luz

class GLShaderProgram
    boolean_accessor :ok

    def initialize(opts)
        #puts '==================== Compiling ===================='

        @vertex_shader = GLVertexShader.new(opts[:vertex_shader_source])
        @fragment_shader = GLFragmentShader.new(opts[:fragment_shader_source])

        @program = glCreateProgram
        glAttachShader(@program, @vertex_shader.shader)
        glAttachShader(@program, @fragment_shader.shader)

        glLinkProgram(@program)

        @uniform_to_location_hash = {}

        if (glGetProgramiv(@program, GL_LINK_STATUS) == true)
            ok!
            #puts 'Compilation Successful'
        else
            not_ok!
            puts "Shader Program compile error:"
            puts glGetProgramInfoLog(@program)
        end
    end

    def using
        glUseProgram(@program)
        yield self
        glUseProgram(0)
    end

    def find_uniform(name)
        location = @uniform_to_location_hash[name]
        return location if location

        location = glGetUniformLocation(@program, name) rescue nil
        puts "shader program ##{@program} uniform '#{name}' not found" unless location
        @uniform_to_location_hash[name] = location
        return location
    end

    def set_3f(name, value)
        id = find_uniform(name)
        glUniform3f(id, *(value.to_a)) if id
    end

    def set_f(name, value)
        id = find_uniform(name)
        glUniform1f(id, value) if id
    end

    def set_int(name, value)
        id = find_uniform(name)
        glUniform1i(id, value) if id
    end
end