lab5

lab5-GeometryPositionColorComposeTransformation

// MVP matrix
Projection = glm::perspective(g_fovy, g_aspect, g_zNear, g_zFar);
View = glm::lookAt(g_eye, g_at, g_up);
spMain.useProgram();
spMain.setUniform(“gProjection”, Projection);
spMain.setUniform(“gView”, View);

// p’ = M3 * M2 * M1 * p (OpenGL uses Column-Major Order)
glm::mat4 Tx = glm::translate(glm::mat4(1.0f), glm::vec3(3.0f, 0.0f, 0.0f)); // RHS x+ right
glm::mat4 Rz = glm::rotate(glm::mat4(1.0f), 45.0f, glm::vec3(0.0f, 0.0f, 1.0f)); // RHS z+ (X->Y rotation)
glm::mat4 S = glm::scale(glm::mat4(1.0f), glm::vec3(2.0f, 2.0f, 2.0f)); // RHS

World = glm::mat4(1.0f);
spMain.setUniform(“gModel”, World);
cube1->draw();

// p’= R T p (red) => translate,  and then rotate
glm::mat4 RT = Rz * Tx;
World = RT;
spMain.setUniform(“gModel”, World);
cube2->draw();

// p’= T R p (green) => rotate, and then translate
glm::mat4 TR = Tx * Rz;
World = TR;
spMain.setUniform(“gModel”, World);
cube3->draw();

// p’= T R S p (blue) => scale, and then rotate, and then translate
glm::mat4 TRS = Tx * Rz * S;
World = TRS;
spMain.setUniform(“gModel”, World);
cube4->draw();

// p’= S R T p (cyan) => translate, and then rotate, and then scale
glm::mat4 SRT = S * Rz * Tx;
World = SRT;
spMain.setUniform(“gModel”, World);
cube5->draw();

// p’= Ra p (yellow green) => rotate by arbitrary axis
glm::mat4 Ra = glm::rotate(glm::mat4(1.0f), 45.0f, glm::vec3(1.0f, 1.0f, 1.0f)));
World = Ra;
spMain.setUniform(“gModel”, World);
cube6->draw();