Add yellow shader

[opengl.git] / assignment1.cpp

diff --git a/assignment1.cpp b/assignment1.cpp
index 43cd62629d323b3e3bc4cc3cebf6b2087d520d16..b3049f0583f956317d1b38e07ec0914aae1acb1f 100644 (file)
--- a/assignment1.cpp
+++ b/assignment1.cpp
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <fstream>
 #include <sstream>
+#include <vector>
 #ifdef __APPLE__
 #include <GL/glew.h>
 #else
@@ -13,9 +14,16 @@
 
 using namespace std;
 
+GLuint* vaos;
+GLuint* progIds;
+
 void display() {
        glClear(GL_COLOR_BUFFER_BIT);
-       glDrawArrays(GL_TRIANGLES, 0, 6);
+       for (int i = 0; i < 2; i++) {
+               glUseProgram(progIds[i]);
+               glBindVertexArray(vaos[i]);
+               glDrawArrays(GL_TRIANGLES, 0, 3);
+       }
        glutSwapBuffers();
 }
 
@@ -45,11 +53,11 @@ void attachShader(GLuint progId, const char* filePath, GLenum type) {
        glAttachShader(progId, shader);
 }
 
-GLuint compileShaders() {
+GLuint compileShaders(char* vertexShader, char* fragmentShader) {
        GLuint progId = glCreateProgram();
 
-       attachShader(progId, "vertex.glsl", GL_VERTEX_SHADER);
-       attachShader(progId, "fragment.glsl", GL_FRAGMENT_SHADER);
+       attachShader(progId, vertexShader, GL_VERTEX_SHADER);
+       attachShader(progId, fragmentShader, GL_FRAGMENT_SHADER);
 
        glLinkProgram(progId);
        GLint success = 0;
@@ -61,68 +69,51 @@ GLuint compileShaders() {
                exit(1);
        }
 
-       glUseProgram(progId);
        return progId;
 }
 
-void generateObjectBuffers() {
-       GLfloat vertices[] = {
-               0.0f, -1.0f, 0.0f,
-               1.0f, -1.0f, 0.0f,
-               0.5f, 1.0f, 0.0f,
+#define BUFFER_OFFSET(i) ((char *)NULL + (i))
 
-               -1.0f, -1.0f, 0.0f,
-               0.0f, -1.0f, 0.0f,
-               -0.5f, 1.0f, 0.0f
-       };
+GLuint setupBuffers(GLfloat* vertices, GLuint progId) {
 
        GLfloat colors[] = {
-               0, 1, 0, 1,
-               1, 0, 0, 1,
-               0, 0, 1, 1,
-               
                0, 1, 0, 1,
                1, 0, 0, 1,
                0, 0, 1, 1
        };
 
-       GLuint numVerts = 6;
+       GLuint numVerts = 3;
 
-       GLuint VBO;
-       glGenBuffers(1, &VBO);
-       glBindBuffer(GL_ARRAY_BUFFER, VBO);
-       glBufferData(GL_ARRAY_BUFFER, numVerts * 7 * sizeof(GLfloat), NULL, GL_STATIC_DRAW);
+       GLuint vbo;
+       glGenBuffers(1, &vbo);
+
+       GLuint vao;
+       glGenVertexArrays(1, &vao);
+
+       GLuint posId = glGetAttribLocation(progId, "vPosition");
+       GLuint colorId = glGetAttribLocation(progId, "vColor");
 
        GLuint vertsLen = numVerts * 3 * sizeof(GLfloat);
        GLuint colorsLen = numVerts * 4 * sizeof(GLfloat);
-       glBufferSubData(GL_ARRAY_BUFFER, 0, vertsLen, vertices);
-       glBufferSubData(GL_ARRAY_BUFFER, vertsLen, colorsLen, colors);
-}
 
-#define BUFFER_OFFSET(i) ((char *)NULL + (i))
+       glBindBuffer(GL_ARRAY_BUFFER, vbo);
+       glBufferData(GL_ARRAY_BUFFER, vertsLen + colorsLen, NULL, GL_STATIC_DRAW);
 
-void linkBuffers(GLuint progId) {
-       GLuint numVerts = 6;
-       GLuint posId = glGetAttribLocation(progId, "vPosition");
-       GLuint colorId = glGetAttribLocation(progId, "vColor");
+       glBufferSubData(GL_ARRAY_BUFFER, 0, vertsLen, vertices);
+       glBufferSubData(GL_ARRAY_BUFFER, vertsLen, colorsLen, colors);
        
-       GLuint vao = 0;
-       glGenVertexArrays(1, &vao);
        glBindVertexArray(vao);
 
        glEnableVertexAttribArray(posId);
-       glVertexAttribPointer(posId, 3, GL_FLOAT, GL_FALSE, 0, 0);
-
        glEnableVertexAttribArray(colorId);
+       
+       glVertexAttribPointer(posId, 3, GL_FLOAT, GL_FALSE, 0, 0);
        glVertexAttribPointer(colorId, 4, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(numVerts * 3 * sizeof(GLfloat)));
 
+       return vao;
 }
 
-void init() {
-       GLuint progId = compileShaders();
-       generateObjectBuffers();
-       linkBuffers(progId);
-       
+void validateProgram(GLuint progId) {
        glValidateProgram(progId);
        
        GLint success;
@@ -135,6 +126,35 @@ void init() {
        }
 }
 
+void init() {
+       GLfloat vertices[2][9] = {
+               {
+                       0.0f, -1.0f, 0.0f,
+                       1.0f, -1.0f, 0.0f,
+                       0.5f, 1.0f, 0.0f
+               },
+
+               {
+                       -1.0f, -1.0f, 0.0f,
+                       0.0f, -1.0f, 0.0f,
+                       -0.5f, 1.0f, 0.0f
+               }
+       };
+
+       vaos = new GLuint[2];
+       progIds = new GLuint[2];
+
+       GLuint progId1 = compileShaders((char*)"vertex.glsl", (char*)"fragment.glsl");
+       vaos[0] = setupBuffers(vertices[0], progId1);
+       progIds[0] = progId1;
+       validateProgram(progId1);
+       
+       GLuint progId2 = compileShaders((char*)"vertex.glsl", (char*)"yellow.glsl");
+       vaos[1] = setupBuffers(vertices[1], progId2);
+       progIds[1] = progId2;
+       validateProgram(progId2);
+}
+
 int main(int argc, char** argv) {
        glutInit(&argc, argv);
        glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB|GLUT_3_2_CORE_PROFILE);