Add yellow shader
authorLuke Lau <luke_lau@icloud.com>
Tue, 18 Sep 2018 10:09:23 +0000 (11:09 +0100)
committerLuke Lau <luke_lau@icloud.com>
Tue, 18 Sep 2018 10:09:23 +0000 (11:09 +0100)
assignment1.cpp
yellow.glsl [new file with mode: 0644]

index fd55f4e..b3049f0 100644 (file)
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <fstream>
 #include <sstream>
+#include <vector>
 #ifdef __APPLE__
 #include <GL/glew.h>
 #else
 using namespace std;
 
 GLuint* vaos;
+GLuint* progIds;
 
 void display() {
        glClear(GL_COLOR_BUFFER_BIT);
        for (int i = 0; i < 2; i++) {
+               glUseProgram(progIds[i]);
                glBindVertexArray(vaos[i]);
                glDrawArrays(GL_TRIANGLES, 0, 3);
        }
@@ -50,11 +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;
@@ -66,26 +69,12 @@ GLuint compileShaders() {
                exit(1);
        }
 
-       glUseProgram(progId);
        return progId;
 }
 
 #define BUFFER_OFFSET(i) ((char *)NULL + (i))
 
-GLuint* setupBuffers(GLuint progId) {
-       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
-               }
-       };
+GLuint setupBuffers(GLfloat* vertices, GLuint progId) {
 
        GLfloat colors[] = {
                0, 1, 0, 1,
@@ -95,11 +84,11 @@ GLuint* setupBuffers(GLuint progId) {
 
        GLuint numVerts = 3;
 
-       GLuint vbos[2];
-       glGenBuffers(2, vbos);
+       GLuint vbo;
+       glGenBuffers(1, &vbo);
 
-       GLuint* vaos = new GLuint[2];
-       glGenVertexArrays(2, vaos);
+       GLuint vao;
+       glGenVertexArrays(1, &vao);
 
        GLuint posId = glGetAttribLocation(progId, "vPosition");
        GLuint colorId = glGetAttribLocation(progId, "vColor");
@@ -107,30 +96,24 @@ GLuint* setupBuffers(GLuint progId) {
        GLuint vertsLen = numVerts * 3 * sizeof(GLfloat);
        GLuint colorsLen = numVerts * 4 * sizeof(GLfloat);
 
-
-       for(int i = 0; i < 2; i++) {
-               glBindBuffer(GL_ARRAY_BUFFER, vbos[i]);
+       glBindBuffer(GL_ARRAY_BUFFER, vbo);
        glBufferData(GL_ARRAY_BUFFER, vertsLen + colorsLen, NULL, GL_STATIC_DRAW);
 
-               glBufferSubData(GL_ARRAY_BUFFER, 0, vertsLen, vertices[i]);
+       glBufferSubData(GL_ARRAY_BUFFER, 0, vertsLen, vertices);
        glBufferSubData(GL_ARRAY_BUFFER, vertsLen, colorsLen, colors);
        
-               glBindVertexArray(vaos[i]);
+       glBindVertexArray(vao);
 
        glEnableVertexAttribArray(posId);
        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 vaos;
+       return vao;
 }
 
-void init() {
-       GLuint progId = compileShaders();
-       vaos = setupBuffers(progId);
-       
+void validateProgram(GLuint progId) {
        glValidateProgram(progId);
        
        GLint success;
@@ -143,6 +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);
diff --git a/yellow.glsl b/yellow.glsl
new file mode 100644 (file)
index 0000000..d1de908
--- /dev/null
@@ -0,0 +1,5 @@
+#version 330
+out vec4 FragColor;
+void main() {
+       FragColor = vec4(1.0, 1.0, 0.0, 1.0);
+}