Experimental: Supersampling, (doesnt work)

source/main.cpp

@@ -44,8 +44,8 @@ GLuint compileShader(GLenum type, const std::string& source) {
     int success;
     glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
     if (!success) {
-        char infoLog[512];
-        glGetShaderInfoLog(shader, 512, nullptr, infoLog);
+        char infoLog[1024];
+        glGetShaderInfoLog(shader, 1024, nullptr, infoLog);
         std::cerr << "Shader compilation failed:\n" << infoLog << std::endl;
         exit(10);
     }
@@ -67,8 +67,8 @@ GLuint createShaderProgram(const std::string& vertexPath, const std::string& fra
     int success;
     glGetProgramiv(program, GL_LINK_STATUS, &success);
     if (!success) {
-        char infoLog[512];
-        glGetProgramInfoLog(program, 512, nullptr, infoLog);
+        char infoLog[1024];
+        glGetProgramInfoLog(program, 1024, nullptr, infoLog);
         std::cerr << "Shader linking failed:\n" << infoLog << std::endl;
         exit(11);
     }
@@ -89,8 +89,8 @@ GLuint createComputeProgram(const std::string& computePath) {
     int success;
     glGetProgramiv(program, GL_LINK_STATUS, &success);
     if (!success) {
-        char infoLog[512];
-        glGetProgramInfoLog(program, 512, nullptr, infoLog);
+        char infoLog[1024];
+        glGetProgramInfoLog(program, 1024, nullptr, infoLog);
         std::cerr << "Compute shader linking failed:\n" << infoLog << std::endl;;
     }
 
@@ -125,12 +125,7 @@ int main() {
     //DEBUG
     std::cout << "OpenGL Version: " << glGetString(GL_VERSION) << std::endl;
 
-    // ERROR: macOS does not support compute shaders in OpenGL < 4.3.
-    // GLuint computeProgram = createComputeProgram(COMPUTE_FILE);
-
     // ----- Vertex Data -----
-    // Cube
-    // Positions
     float vertices[] = {
         // positions
         -1.0f, -1.0f, 0.0f,
@@ -161,22 +156,11 @@ int main() {
     glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,3*sizeof(float),(void*)0);
     glEnableVertexAttribArray(0);
 
-    // color - FRAGMENT SHADER
-    glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,3*sizeof(float),(void*)(3*sizeof(float)));
-    glEnableVertexAttribArray(1);
-
     glBindBuffer(GL_ARRAY_BUFFER,0);
-    // glBindVertexArray(0);
 
     // Load shaders
     GLuint shaderProgram = createShaderProgram(VERTEX_FILE, FRAGMENT_FILE);
 
-    // Check if shader program was created successfully
-    if (shaderProgram == 0) {
-        std::cerr << "Failed to create shader programs.\n";
-        return -1;
-    }
-
     // Caulculate model, view, projection matrices
     glm::mat4 model = glm::mat4(1.0f);
     glm::mat4 view = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, -1.0f));
@@ -191,21 +175,55 @@ int main() {
     glUniformMatrix4fv((int) viewLoc, 1, GL_FALSE, glm::value_ptr(view));
     glUniformMatrix4fv((int) projLoc, 1, GL_FALSE, glm::value_ptr(projection));
 
-
+    // Query important uniform locations (we'll keep them around)
     GLint resLoc = glGetUniformLocation(shaderProgram, "u_resolution");
-    glUniform2f(resLoc, SCR_WIDTH, SCR_HEIGHT); // hardcode for now
-
     GLint timeLoc = glGetUniformLocation(shaderProgram, "u_time");
     GLint scaleLoc = glGetUniformLocation(shaderProgram, "u_scale");
     GLint mouseLoc = glGetUniformLocation(shaderProgram, "u_mouse");
 
     glEnable(GL_MULTISAMPLE);
 
+    // --- Supersampling FBO ---
+    int scaleFactor = 2; // try 2 or 4 for smoother output
+    int fbWidth = (int)SCR_WIDTH * scaleFactor;
+    int fbHeight = (int)SCR_HEIGHT * scaleFactor;
+
+    unsigned int fbo, colorTex, rbo;
+    glGenFramebuffers(1, &fbo);
+    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+
+    // Color texture
+    glGenTextures(1, &colorTex);
+    glBindTexture(GL_TEXTURE_2D, colorTex);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, fbWidth, fbHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+    // filtering + wrap
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorTex, 0);
+
+    // Depth/stencil buffer
+    glGenRenderbuffers(1, &rbo);
+    glBindRenderbuffer(GL_RENDERBUFFER, rbo);
+    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, fbWidth, fbHeight);
+    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rbo);
+
+    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+        std::cout << "ERROR: Framebuffer not complete!" << std::endl;
+
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    // --------------------------
+
+    // set the shader resolution to the FBO size (important!)
+    glUseProgram(shaderProgram);
+    glUniform2f(resLoc, SCR_WIDTH, SCR_HEIGHT);
+
     float scale = 1.0f;
     int frameCount = 0;
     float mousePos[2] = {0.0f, 0.0f};
 
-
     // FPS tracking
     double lastTime = glfwGetTime();   // when we last printed FPS
     double fps = 0.0;
@@ -223,7 +241,7 @@ int main() {
         // Input
         glfwPollEvents();
 
-
+        // Shader hot-reload
         if (glfwGetKey(window, GLFW_KEY_R) == GLFW_PRESS) {
             glDeleteProgram(shaderProgram);
             shaderProgram = createShaderProgram(VERTEX_FILE, FRAGMENT_FILE);
@@ -236,11 +254,14 @@ int main() {
             glUniformMatrix4fv((int) viewLoc, 1, GL_FALSE, glm::value_ptr(view));
             glUniformMatrix4fv((int) projLoc, 1, GL_FALSE, glm::value_ptr(projection));
 
+            // Re-query uniforms and set resolution to FBO size (IMPORTANT)
             resLoc = glGetUniformLocation(shaderProgram, "u_resolution");
-            glUniform2f(resLoc, SCR_WIDTH, SCR_HEIGHT); // hardcode for now
-
             timeLoc = glGetUniformLocation(shaderProgram, "u_time");
             scaleLoc = glGetUniformLocation(shaderProgram, "u_scale");
+            mouseLoc = glGetUniformLocation(shaderProgram, "u_mouse");
+
+            glUseProgram(shaderProgram);
+            glUniform2f(resLoc, (float)fbWidth, (float)fbHeight);
 
             std::cout << "Shaders recompiled!\n";
         }
@@ -256,10 +277,12 @@ int main() {
             if (scale < 0.1f) scale = 0.1f; // Min zoom
         }
 
-        // --- FPS Counter ---
+        // increment frame count (for FPS)
+        frameCount++;
+
+        // --- FPS Counter (print to console every second) ---
         double currentTime = glfwGetTime();
         double delta = currentTime - lastTime;
-
         if (delta >= 1.0) { // print every ~1 second
             fps = double(frameCount) / delta;
             std::cout << "FPS: " << fps
@@ -272,18 +295,31 @@ int main() {
             lastTime = currentTime;
         }
 
+        // --- Render into high-res FBO ---
+        glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+        glViewport(0, 0, fbWidth, fbHeight);
+        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+        // Use shader & set uniforms
+        glUseProgram(shaderProgram);
         glUniform1f(timeLoc, timeValue);
         glUniform1f(scaleLoc, scale);
         glUniform2f(mouseLoc, mousePos[0], mousePos[1]);
+        // (u_resolution already set to fbWidth, fbHeight)
 
-        frameCount++;
-
-        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
-        glClear(GL_COLOR_BUFFER_BIT);
         glBindVertexArray(VAO);
         glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
 
-        glUseProgram(shaderProgram);
+        // --- Blit back to screen ---
+        glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
+        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+        glBlitFramebuffer(0, 0, fbWidth, fbHeight,
+                          0, 0, (int)SCR_WIDTH, (int)SCR_HEIGHT,
+                          GL_COLOR_BUFFER_BIT, GL_LINEAR);
+
+        glBindFramebuffer(GL_FRAMEBUFFER, 0);
+        glViewport(0, 0, (int)SCR_WIDTH, (int)SCR_HEIGHT);
 
         glfwSwapBuffers(window);
     }
@@ -297,4 +333,3 @@ int main() {
     glfwTerminate();
     return 0;
 }
-