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/**
* "Brick" shader demo. Uses the example shaders from chapter 6 of
* the OpenGL Shading Language "orange" book.
* 10 Jan 2007
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glew.h>
#include <GL/glut.h>
#include "shaderutil.h"
static char *FragProgFile = "CH06-brick.frag";
static char *VertProgFile = "CH06-brick.vert";
/* program/shader objects */
static GLuint fragShader;
static GLuint vertShader;
static GLuint program;
static struct uniform_info Uniforms[] = {
/* vert */
{ "LightPosition", 3, GL_FLOAT, { 0.1, 0.1, 9.0, 0}, -1 },
/* frag */
{ "BrickColor", 3, GL_FLOAT, { 0.8, 0.2, 0.2, 0 }, -1 },
{ "MortarColor", 3, GL_FLOAT, { 0.6, 0.6, 0.6, 0 }, -1 },
{ "BrickSize", 2, GL_FLOAT, { 1.0, 0.3, 0, 0 }, -1 },
{ "BrickPct", 2, GL_FLOAT, { 0.9, 0.8, 0, 0 }, -1 },
END_OF_UNIFORMS
};
static GLint win = 0;
static GLfloat xRot = 0.0f, yRot = 0.0f, zRot = 0.0f;
static void
Redisplay(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotatef(xRot, 1.0f, 0.0f, 0.0f);
glRotatef(yRot, 0.0f, 1.0f, 0.0f);
glRotatef(zRot, 0.0f, 0.0f, 1.0f);
glBegin(GL_POLYGON);
glTexCoord2f(0, 0); glVertex2f(-2, -2);
glTexCoord2f(1, 0); glVertex2f( 2, -2);
glTexCoord2f(1, 1); glVertex2f( 2, 2);
glTexCoord2f(0, 1); glVertex2f(-2, 2);
glEnd();
glPopMatrix();
glutSwapBuffers();
}
static void
Reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0f, 0.0f, -15.0f);
}
static void
CleanUp(void)
{
glDeleteShader(fragShader);
glDeleteShader(vertShader);
glDeleteProgram(program);
glutDestroyWindow(win);
}
static void
Key(unsigned char key, int x, int y)
{
(void) x;
(void) y;
switch(key) {
case 'z':
zRot -= 1.0;
break;
case 'Z':
zRot += 1.0;
break;
case 27:
CleanUp();
exit(0);
break;
}
glutPostRedisplay();
}
static void
SpecialKey(int key, int x, int y)
{
const GLfloat step = 3.0f;
(void) x;
(void) y;
switch(key) {
case GLUT_KEY_UP:
xRot -= step;
break;
case GLUT_KEY_DOWN:
xRot += step;
break;
case GLUT_KEY_LEFT:
yRot -= step;
break;
case GLUT_KEY_RIGHT:
yRot += step;
break;
}
glutPostRedisplay();
}
static void
Init(void)
{
if (!ShadersSupported())
exit(1);
vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
program = LinkShaders(vertShader, fragShader);
glUseProgram(program);
InitUniforms(program, Uniforms);
assert(glGetError() == 0);
glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
assert(glIsProgram(program));
assert(glIsShader(fragShader));
assert(glIsShader(vertShader));
glColor3f(1, 0, 0);
}
static void
ParseOptions(int argc, char *argv[])
{
int i;
for (i = 1; i < argc; i++) {
if (strcmp(argv[i], "-fs") == 0) {
FragProgFile = argv[i+1];
}
else if (strcmp(argv[i], "-vs") == 0) {
VertProgFile = argv[i+1];
}
}
}
int
main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitWindowPosition( 0, 0);
glutInitWindowSize(400, 400);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
win = glutCreateWindow(argv[0]);
glewInit();
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutSpecialFunc(SpecialKey);
glutDisplayFunc(Redisplay);
ParseOptions(argc, argv);
Init();
glutMainLoop();
return 0;
}
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