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Example OpenGL3.2 buffer/shader usage
/*
Original: 1562391 by branan
Updated to use GLFW so it works on Mac OS X Lion
*/
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#define GLFW_NO_GLU
#define GLFW_INCLUDE_GL3
#include <GL/glfw.h>
GLfloat vert_data[] = {
-1.0, -1.0, 0.0,
1.0, -1.0, 0.0,
0.0, 1.0, 0.0,
};
GLfloat col_data[] = {
1.0, 0.0, 0.0,
0.0, 1.0, 0.0,
0.0, 0.0, 1.0
};
#define POSITION_ATTRIB 0
#define COLOR_ATTRIB 1
const char* vert_shader =
"\
#version 150\n\
\n\
in vec3 position;\n\
in vec3 color;\n\
out vec3 vcol;\n\
\n\
void main(void) { \n\
vcol = color;\n\
gl_Position = vec4(position, 1.0);\n\
}\n\
";
const char* frag_shader =
"\
#version 150\n\
\n\
in vec3 vcol;\n\
out vec4 fcol;\n\
\n\
void main(void) { \n\
fcol = vec4(vcol,1.0);\n\
}\n\
";
void init(void) {
GLuint vao;
GLuint bufs[2];
glGenVertexArrays(1, &vao);
glGenBuffers(2, bufs);
glBindVertexArray(vao);
glEnableVertexAttribArray(POSITION_ATTRIB);
glEnableVertexAttribArray(COLOR_ATTRIB);
glBindBuffer(GL_ARRAY_BUFFER, bufs[0]);
glBufferData(GL_ARRAY_BUFFER, 3*3*sizeof(GLfloat), vert_data, GL_STATIC_DRAW);
glVertexAttribPointer(POSITION_ATTRIB, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, bufs[1]);
glBufferData(GL_ARRAY_BUFFER, 3*3*sizeof(GLfloat), col_data, GL_STATIC_DRAW);
glVertexAttribPointer(COLOR_ATTRIB, 3, GL_FLOAT, GL_FALSE, 0, 0);
GLuint prog;
GLuint vert;
GLuint frag;
prog = glCreateProgram();
vert = glCreateShader(GL_VERTEX_SHADER);
frag = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(vert, 1, &vert_shader, 0);
glShaderSource(frag, 1, &frag_shader, 0);
glCompileShader(vert);
glCompileShader(frag);
glAttachShader(prog, vert);
glAttachShader(prog, frag);
glBindAttribLocation(prog, POSITION_ATTRIB, "position");
glBindAttribLocation(prog, COLOR_ATTRIB, "color");
glLinkProgram(prog);
glUseProgram(prog);
}
void render(void) {
glClear(GL_COLOR_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers();
}
int main(int argc, char** argv) {
if (GL_TRUE != glfwInit())
{
fprintf(stderr, "ERROR: Unable to initialize GLFW\n");
}
glfwEnable(GLFW_AUTO_POLL_EVENTS); /* No explicit call to glfwPollEvents() */
glfwOpenWindowHint(GLFW_WINDOW_NO_RESIZE, GL_TRUE);
glfwOpenWindowHint(GLFW_OPENGL_VERSION_MAJOR, 3);
glfwOpenWindowHint(GLFW_OPENGL_VERSION_MINOR, 2);
glfwOpenWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwOpenWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
if (GL_TRUE != glfwOpenWindow(800, 600, 0, 0, 0, 0, 0, 0, GLFW_WINDOW))
{
fprintf(stderr, "ERROR: Unable to create the OpenGL context and associated window\n");
exit(EXIT_FAILURE);
}
init();
do {
render();
} while(glfwGetKey( GLFW_KEY_ESC ) != GLFW_PRESS &&
glfwGetKey( 'Q' ) != GLFW_PRESS &&
glfwGetWindowParam( GLFW_OPENED ) );
glfwTerminate();
exit(0);
}
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