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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <GL/glew.h>
#include <GL/glut.h>
static void Init(void)
{
static const char *modulate2D =
"!!ARBfp1.0\n"
"MUL result.depth.z, fragment.color.z, {.1}.x; \n"
"MOV result.color.xy, fragment.color; \n"
"END"
;
GLuint modulateProg;
if (!GLEW_ARB_fragment_program) {
printf("Error: GL_ARB_fragment_program not supported!\n");
exit(1);
}
printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
/* Setup the fragment program */
glGenProgramsARB(1, &modulateProg);
glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, modulateProg);
glProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
strlen(modulate2D), (const GLubyte *)modulate2D);
printf("glGetError = 0x%x\n", (int) glGetError());
printf("glError(GL_PROGRAM_ERROR_STRING_ARB) = %s\n",
(char *) glGetString(GL_PROGRAM_ERROR_STRING_ARB));
glEnable(GL_FRAGMENT_PROGRAM_ARB);
glClearColor(.3, .3, .3, 0);
}
static void Reshape(int width, int height)
{
glViewport(0, 0, (GLint)width, (GLint)height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
glMatrixMode(GL_MODELVIEW);
}
static void Key(unsigned char key, int x, int y)
{
switch (key) {
case 27:
exit(1);
default:
break;
}
glutPostRedisplay();
}
static void Draw(void)
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
glBegin(GL_TRIANGLES);
glColor4f(.8,0,.5,0);
glVertex3f( 0.9, -0.9, -30.0);
glVertex3f( 0.9, 0.9, -30.0);
glVertex3f(-0.9, 0.0, -30.0);
glColor4f(0,.8,.7,0);
glVertex3f(-0.9, -0.9, -40.0);
glColor4f(0,.8,.7,0);
glVertex3f(-0.9, 0.9, -40.0);
glColor4f(0,.8,.3,0);
glVertex3f( 0.9, 0.0, -40.0);
glEnd();
glFlush();
}
int main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitWindowPosition(0, 0); glutInitWindowSize( 300, 300);
glutInitDisplayMode(GLUT_DEPTH | GLUT_RGB | GLUT_SINGLE);
if (glutCreateWindow("Depth Test") == GL_FALSE) {
exit(1);
}
glewInit();
Init();
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutDisplayFunc(Draw);
glutMainLoop();
return 0;
}
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