X-Git-Url: https://git.lukelau.me/?p=opengl.git;a=blobdiff_plain;f=assignment1.cpp;h=b3049f0583f956317d1b38e07ec0914aae1acb1f;hp=43cd62629d323b3e3bc4cc3cebf6b2087d520d16;hb=6cbf05fce9821efdbbb141c6a0dbff6e6745fbc0;hpb=1dcbad027a4537b550766e9053a4418e8256c81c

diff --git a/assignment1.cpp b/assignment1.cpp
index 43cd626..b3049f0 100644
--- 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);