real instanced rendering

src/main.cpp

@@ -5,6 +5,7 @@
 #include <glm/glm.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtc/type_ptr.hpp>
+#include <random>
 
 #include <GL/glew.h>
 #include <SDL2/SDL_opengl.h>
@@ -121,10 +122,11 @@ void printProgramLog( GLuint program )
 class SDLGLGLWindow {
 
     /* array buffers */
-    GLuint gVBO = 0;
-    GLuint quadVBO = 0;
-    GLuint gIBO = 0;
-    GLuint gVAO = 0;
+    unsigned int gVBO = 0;
+    unsigned int quadVBO = 0;
+//    unsigned int gIBO = 0;
+    unsigned int gVAO = 0;
+    unsigned int instance_VBO;
     unsigned int lightVAO;
     unsigned int quadVAO;
     unsigned int framebuffer;
@@ -133,6 +135,7 @@ class SDLGLGLWindow {
     unsigned int texture[2];
     unsigned int cubemap;
 
+    glm::vec3 *translations = new glm::vec3[100000];
     
     glm::vec3 cubePositions[10] = {
         glm::vec3( 0.0f,  0.0f,  0.0f), 
@@ -291,30 +294,29 @@ class SDLGLGLWindow {
         glBindFramebuffer(GL_FRAMEBUFFER, 0); // unbind
         glCheckError();
 
-        glm::vec3 *translations = new glm::vec3[100];
 
-        int index = 0;
-        float offset = 0.1f;
-        for (int y = -10; y < 10; y += 2) {
-            for (int x = -10; x < 10; x += 4) {
-                for (int z = -10; z < 10; z += 4) {
-                    if (index >= 100) {
-                        goto yeetbreak;
-                    }
-                    translations[index++] = glm::vec3(x,y,z);
-                }
-            }
+        std::default_random_engine generator;
+        std::uniform_real_distribution<float> distribution(-50,50);
+
+        for (int i = 0; i < 100000; i ++) {
+            float x = distribution(generator) ;
+            float y = distribution(generator) ;
+            float z = distribution(generator) ;
+            translations[i] = glm::vec3(i,y,z);
         }
-yeetbreak:
-        
 
         shader->use();
 
-        for (unsigned int i = 0; i < 100; i++) {
-            shader->setVec3("offsets[" + std::to_string(i) + "]", translations[i]);
-        }
+        glGenBuffers(1, &instance_VBO);
+        glBindBuffer(GL_ARRAY_BUFFER, instance_VBO);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec3) * 100, &translations[0], GL_STATIC_DRAW);
+
+
+        glCheckError();
+        glCheckError();
+        glCheckError();
+
 
-        delete[] translations;
 
         /* textures */
 
@@ -465,6 +467,12 @@ yeetbreak:
         glEnableVertexAttribArray(2);
         glCheckError();
 
+        glBindBuffer(GL_ARRAY_BUFFER, instance_VBO);
+        glVertexAttribPointer(3,3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), NULL);
+        glVertexAttribDivisor(3,1);
+        glBindBuffer(GL_ARRAY_BUFFER, 0);
+        glEnableVertexAttribArray(3);
+
         /*********** ENDCUBES **************/
 
 
@@ -652,7 +660,7 @@ yeetbreak:
         glBindVertexArray(gVAO);
         glBindTexture(GL_TEXTURE_2D, texture[0]);
         glCheckError();
-        glDrawArraysInstanced(GL_TRIANGLES, 0,36,100);
+        glDrawArraysInstanced(GL_TRIANGLES, 0,36,100000);
         glCheckError();
 
         /*

src/shaders/instanced.vert

@@ -3,23 +3,20 @@
 layout (location = 0) in vec3 LVertexPos2D;
 layout (location = 1) in vec3 aNormal;
 layout (location = 2) in vec2 aTexCoords;
+layout (location = 3) in vec3 offset;
 
 out vec3 theTexCoord;
 
 uniform mat4 model;
 uniform mat4 view;
 uniform mat4 projection;
-uniform bool skyboxON;
 
 out vec3 Normal;
 out vec3 FragPos;
 
-uniform vec3 offsets[100];
-
 void main() 
 { 
-    vec3 offset = offsets[gl_InstanceID];
-    vec4 pos = (vec4( LVertexPos2D, 1.0) - vec4(offset, 0));
+    vec4 pos = (vec4( LVertexPos2D, 1.0) + vec4(offset, 0));
 
     gl_Position = projection * view * (model) * pos;