+
+DirectionalLighting::DirectionalLighting()
+: program()
+, light_direction(1.0f, 3.0f, 2.0f)
+, light_color(0.9f, 0.9f, 0.9f)
+, vp(1.0f)
+, m_handle(0)
+, mvp_handle(0)
+, light_direction_handle(0)
+, light_color_handle(0) {
+ program.LoadShader(
+ GL_VERTEX_SHADER,
+ "#version 330 core\n"
+ "layout(location = 0) in vec3 vtx_position;\n"
+ "layout(location = 1) in vec3 vtx_color;\n"
+ "layout(location = 2) in vec3 vtx_normal;\n"
+ "uniform mat4 M;\n"
+ "uniform mat4 MVP;\n"
+ "out vec3 frag_color;\n"
+ "out vec3 normal;\n"
+ "void main() {\n"
+ "gl_Position = MVP * vec4(vtx_position, 1);\n"
+ "normal = (M * vec4(vtx_normal, 0)).xyz;\n"
+ "frag_color = vtx_color;\n"
+ "}\n"
+ );
+ program.LoadShader(
+ GL_FRAGMENT_SHADER,
+ "#version 330 core\n"
+ "in vec3 frag_color;\n"
+ "in vec3 normal;\n"
+ "uniform vec3 light_direction;\n"
+ "uniform vec3 light_color;\n"
+ "out vec3 color;\n"
+ "void main() {\n"
+ "vec3 ambient = vec3(0.1, 0.1, 0.1) * frag_color;\n"
+ "vec3 n = normalize(normal);\n"
+ "vec3 l = normalize(light_direction);\n"
+ "float cos_theta = clamp(dot(n, l), 0, 1);\n"
+ "color = ambient + frag_color * light_color * cos_theta;\n"
+ "}\n"
+ );
+ program.Link();
+ if (!program.Linked()) {
+ program.Log(std::cerr);
+ throw std::runtime_error("link program");
+ }
+
+ m_handle = program.UniformLocation("M");
+ mvp_handle = program.UniformLocation("MVP");
+ light_direction_handle = program.UniformLocation("light_direction");
+ light_color_handle = program.UniformLocation("light_color");
+}
+
+
+void DirectionalLighting::Activate() {
+ GLContext::EnableDepthTest();
+ GLContext::EnableBackfaceCulling();
+ program.Use();
+
+ glUniform3f(light_direction_handle, light_direction.x, light_direction.y, light_direction.z);
+ glUniform3f(light_color_handle, light_color.x, light_color.y, light_color.z);
+}
+
+void DirectionalLighting::SetM(const glm::mat4 &m) {
+ glm::mat4 mvp(vp * m);
+ glUniformMatrix4fv(m_handle, 1, GL_FALSE, &m[0][0]);
+ glUniformMatrix4fv(mvp_handle, 1, GL_FALSE, &mvp[0][0]);
+}
+
+void DirectionalLighting::SetVP(const glm::mat4 &v, const glm::mat4 &p) {
+ vp = p * v;
+}
+
+void DirectionalLighting::SetMVP(const glm::mat4 &m, const glm::mat4 &v, const glm::mat4 &p) {
+ SetVP(v, p);
+ SetM(m);
+}
+