Move PVM matrix multiplication from vertex to tessellation eval shader

shaders/tessellation_eval.glsl

@@ -2,6 +2,14 @@
 
 layout(quads, equal_spacing, ccw) in;  // Define the type of patch (e.g., quads)
 
+layout(location = 0) uniform mat4 M;
+
+layout(std140, binding = 0) uniform SceneUniforms
+{
+    mat4 PV;	//camera projection * view matrix
+    vec4 eye_w;	//world-space eye position
+};
+
 out vec3 frag_position;  // Ensure this matches the input in fragment.glsl
 
 void main()
@@ -13,5 +21,5 @@ void main()
     
     frag_position = pos;
 
-    gl_Position = vec4(pos, 1.0);
+    gl_Position = PV*M*vec4(pos, 1.0);
 }

shaders/vertex.glsl

@@ -1,4 +1,11 @@
 #version 430
+layout(location = 0) uniform mat4 M;
+
+layout(std140, binding = 0) uniform SceneUniforms
+{
+    mat4 PV;	//camera projection * view matrix
+    vec4 eye_w;	//world-space eye position
+};
 
 layout(location = 0) in vec3 pos_attrib;
 layout(location = 1) in vec2 tex_coord_attrib;

source/scene.cpp

@@ -41,10 +41,11 @@ Scene::Scene(int width, int height)
     quad_shader_program_(-1),
     vao_(-1), 
     quad_vao_(-1),
-    angle_(0.0f), 
+    angle_(-glm::pi<float>() / 2.0f), 
     scale_(1.0f), 
     aspect_(static_cast<float>(width) / static_cast<float>(height)), 
-    near_z_(0.1f), far_z_(100.0f), 
+    near_z_(0.01f), 
+    far_z_(100.0f), 
     fov_(glm::pi<float>() / 4.0f) 
 {}
 
@@ -80,11 +81,19 @@ void Scene::Init() {
 void Scene::InitBuffers() {
     GLuint patch_vbo;
     // Quad vertices in 3D space
+    // float patchVertices[] = {
+    //     -0.5f, 0.0f, -0.5f,  // Bottom-left
+    //      0.5f, 0.0f, -0.5f,  // Bottom-right
+    //      0.5f, 0.0f,  0.5f,  // Top-right
+    //     -0.5f, 0.0f,  0.5f   // Top-left
+         
+    // };
+
     float patchVertices[] = {
         -0.5f, -0.5f, 0.0f,  // Bottom-left
          0.5f, -0.5f, 0.0f,  // Bottom-right
-         0.5f,  0.5f, 0.0f,   // Top-right
+         0.5f,  0.5f, 0.0f,  // Top-right
-        -0.5f,  0.5f, 0.0f  // Top-left
+        -0.5f,  0.5f, 0.0f   // Top-left
          
     };
 
@@ -152,20 +161,20 @@ void Scene::Display(GLFWwindow* window) {
 
     glUseProgram(shader_program_);
 
-    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 
-    view_matrix_ = glm::lookAt(glm::vec3(Uniforms::SceneData.eye_w), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
+    view_matrix_ = glm::lookAt(glm::vec3(0.0f, 2.0f, 3.0f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
     Uniforms::SceneData.PV = projection_matrix_ * view_matrix_; // Projection-View matrix
     Uniforms::BufferSceneData();
 
-    glm::mat4 model_matrix = glm::rotate(angle_, glm::vec3(0.0f, 1.0f, 0.0f)) * glm::scale(glm::vec3(scale_));
+    glm::mat4 model_matrix = glm::rotate(angle_, glm::vec3(1.0f, 0.0f, 0.0f)) * glm::scale(glm::vec3(scale_));
     glUniformMatrix4fv(Uniforms::UniformLocs::M, 1, false, glm::value_ptr(model_matrix));
 
     glBindVertexArray(vao_);
     glPatchParameteri(GL_PATCH_VERTICES, 4);
     glDrawArrays(GL_PATCHES, 0, 4);
 
-    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+    //glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 
     fbo_.Unbind();