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/**
* Procedural Bump Mapping demo. Uses the example shaders from
* chapter 11 of the OpenGL Shading Language "orange" book.
* 16 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 = "CH11-bumpmap.frag";
static char *VertProgFile = "CH11-bumpmap.vert";
/* program/shader objects */
static GLuint fragShader;
static GLuint vertShader;
static GLuint program;
static struct uniform_info Uniforms[] = {
{ "LightPosition", 1, GL_FLOAT_VEC3, { 0.57737, 0.57735, 0.57735, 0.0 }, -1 },
{ "SurfaceColor", 1, GL_FLOAT_VEC3, { 0.8, 0.8, 0.2, 0 }, -1 },
{ "BumpDensity", 1, GL_FLOAT, { 10.0, 0, 0, 0 }, -1 },
{ "BumpSize", 1, GL_FLOAT, { 0.125, 0, 0, 0 }, -1 },
{ "SpecularFactor", 1, GL_FLOAT, { 0.5, 0, 0, 0 }, -1 },
END_OF_UNIFORMS
};
static GLint win = 0;
static GLfloat xRot = 20.0f, yRot = 0.0f, zRot = 0.0f;
static GLuint tangentAttrib;
static GLboolean Anim = GL_FALSE;
static void
CheckError(int line)
{
GLenum err = glGetError();
if (err) {
printf("GL Error %s (0x%x) at line %d\n",
gluErrorString(err), (int) err, line);
}
}
/*
* Draw a square, specifying normal and tangent vectors.
*/
static void
Square(GLfloat size)
{
glNormal3f(0, 0, 1);
glVertexAttrib3f(tangentAttrib, 1, 0, 0);
glBegin(GL_POLYGON);
glTexCoord2f(0, 0); glVertex2f(-size, -size);
glTexCoord2f(1, 0); glVertex2f( size, -size);
glTexCoord2f(1, 1); glVertex2f( size, size);
glTexCoord2f(0, 1); glVertex2f(-size, size);
glEnd();
}
static void
Cube(GLfloat size)
{
/* +X */
glPushMatrix();
glRotatef(90, 0, 1, 0);
glTranslatef(0, 0, size);
Square(size);
glPopMatrix();
/* -X */
glPushMatrix();
glRotatef(-90, 0, 1, 0);
glTranslatef(0, 0, size);
Square(size);
glPopMatrix();
/* +Y */
glPushMatrix();
glRotatef(90, 1, 0, 0);
glTranslatef(0, 0, size);
Square(size);
glPopMatrix();
/* -Y */
glPushMatrix();
glRotatef(-90, 1, 0, 0);
glTranslatef(0, 0, size);
Square(size);
glPopMatrix();
/* +Z */
glPushMatrix();
glTranslatef(0, 0, size);
Square(size);
glPopMatrix();
/* -Z */
glPushMatrix();
glRotatef(180, 0, 1, 0);
glTranslatef(0, 0, size);
Square(size);
glPopMatrix();
}
static void
Idle(void)
{
GLint t = glutGet(GLUT_ELAPSED_TIME);
yRot = t * 0.05;
glutPostRedisplay();
}
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);
Cube(1.5);
glPopMatrix();
CheckError(__LINE__);
glutSwapBuffers();
}
static void
Reshape(int width, int height)
{
float ar = (float) width / (float) height;
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-ar, ar, -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)
{
const GLfloat step = 2.0;
(void) x;
(void) y;
switch(key) {
case 'a':
Anim = !Anim;
glutIdleFunc(Anim ? Idle : NULL);
break;
case 'z':
zRot += step;
break;
case 'Z':
zRot -= step;
break;
case 27:
CleanUp();
exit(0);
break;
}
glutPostRedisplay();
}
static void
SpecialKey(int key, int x, int y)
{
const GLfloat step = 2.0;
(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);
assert(glIsProgram(program));
assert(glIsShader(fragShader));
assert(glIsShader(vertShader));
assert(glGetError() == 0);
CheckError(__LINE__);
SetUniformValues(program, Uniforms);
PrintUniforms(Uniforms);
CheckError(__LINE__);
tangentAttrib = glGetAttribLocation(program, "Tangent");
printf("Tangent Attrib: %d\n", tangentAttrib);
assert(tangentAttrib >= 0);
CheckError(__LINE__);
glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
glEnable(GL_DEPTH_TEST);
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);
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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