Hello.
I've managed to write some basic lighting shaders and work them into a Windows GL program using the ARB extensions. I know everything works, because I can write a pair of trivial shaders and get what I expect. However, my current shaders, which rely on application-set lighting variables (set by GL's normal lighting functions) won't work. The shaders are written correctly, as far as I know, and they are read, compiled, linked, and used without problem, as far as I can tell. I think the problem lies in the way I am communicating from my application to the shaders, but I can't see any problems. All help is appreciated.
Thanks.
P.S. The code is very ugly, I know, but I'm just trying to get it to work, ATM.
[vert.gl]
varying vec4 diffuse, ambient;
varying vec3 normal, lightDir, halfVector;
void main(void) {
normal = normalize(gl_NormalMatrix * gl_Normal);
lightDir = normalize(vec3(gl_LightSource[0].position));
halfVector = normalize(gl_LightSource[0].halfVector.xyz);
diffuse = gl_FrontMaterial.diffuse * gl_LightSource[0].diffuse;
ambient = gl_FrontMaterial.ambient * gl_LightSource[0].ambient;
ambient += gl_LightModel.ambient * gl_FrontMaterial.ambient;
gl_Position = ftransform();
}
[frag.gl]
varying vec4 diffuse, ambient;
varying vec3 normal, lightDir, halfVector;
void main(void) {
vec3 n, halfV;
float NdotL, NdotHV;
vec4 color = ambient;
n = normalize(normal);
NdotL = max(dot(n, lightDir), 0.0);
if(NdotL > 0.0) {
color += diffuse * NdotL;
halfV = normalize(halfVector);
NdotHV = max(dot(n, halfV), 0.0);
color += gl_FrontMaterial.specular *
gl_LightSource[0].specular *
pow(NdotHV, gl_FrontMaterial.shininess);
}
gl_FragColor = color;
}
[main.cpp]
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>
#include <GL/glext.h>
#include <stdio.h>
#include <stdlib.h>
#include <fstream>
void init(void);
void display(void);
void reshape(int, int);
void idle(void);
int main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutInitWindowPosition(100, 100);
glutInitWindowSize(640, 480);
glutCreateWindow(argv[0]);
init();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutIdleFunc(idle);
glutMainLoop();
return 0;
}
char *textFileRead(char *fn)
{
FILE *fp;
char *content = NULL;
int count=0;
if (fn != NULL) {
fp = fopen(fn,"rt");
if (fp != NULL) {
fseek(fp, 0, SEEK_END);
count = ftell(fp);
rewind(fp);
if (count > 0) {
content = (char *)malloc(sizeof(char) * (count+1));
count = fread(content,sizeof(char),count,fp);
content[count] = '\0';
}
fclose(fp);
}
}
return content;
}
void init(void)
{
glColor3f(1, 1, 1);
glClearColor(0, 0, 0, 0);
glClearDepth(1);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
GLfloat matSpec[] = {1.0, 1.0, 1.0, 1.0};
GLfloat matShininess[] = {50.0};
GLfloat lightPosition[] = {0.0, 0.0, 0.0, 0.0};
GLfloat whiteLight[] = {1.0, 1.0, 1.0, 1.0};
GLfloat lmodelAmbient[] = {0.1, 0.1, 0.1, 1.0};
glMaterialfv(GL_FRONT, GL_SPECULAR, matSpec);
glMaterialfv(GL_FRONT, GL_SHININESS, matShininess);
glMaterialfv(GL_FRONT, GL_AMBIENT, lmodelAmbient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, whiteLight);
glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
glLightfv(GL_LIGHT0, GL_DIFFUSE, whiteLight);
glLightfv(GL_LIGHT0, GL_SPECULAR, whiteLight);
glLightfv(GL_LIGHT0, GL_AMBIENT, lmodelAmbient);
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodelAmbient);
PFNGLCREATESHADEROBJECTARBPROC glCreateShaderObjectARB = (PFNGLCREATESHADEROBJECTARBPROC)wglGetProcAddress("glCreateShaderObjectARB");
PFNGLSHADERSOURCEARBPROC glShaderSourceARB = (PFNGLSHADERSOURCEARBPROC)wglGetProcAddress("glShaderSourceARB");
PFNGLCOMPILESHADERARBPROC glCompileShaderARB = (PFNGLCOMPILESHADERARBPROC)wglGetProcAddress("glCompileShaderARB");
PFNGLCREATEPROGRAMOBJECTARBPROC glCreateProgramObjectARB = (PFNGLCREATEPROGRAMOBJECTARBPROC)wglGetProcAddress("glCreateProgramObjectARB");
PFNGLATTACHOBJECTARBPROC glAttachObjectARB = (PFNGLATTACHOBJECTARBPROC)wglGetProcAddress("glAttachObjectARB");
PFNGLLINKPROGRAMARBPROC glLinkProgramARB = (PFNGLLINKPROGRAMARBPROC)wglGetProcAddress("glLinkProgramARB");
PFNGLUSEPROGRAMOBJECTARBPROC glUseProgramObjectARB = (PFNGLUSEPROGRAMOBJECTARBPROC)wglGetProcAddress("glUseProgramObjectARB");
PFNGLGETINFOLOGARBPROC glGetInfoLogARB = (PFNGLGETINFOLOGARBPROC)wglGetProcAddress("glGetInfoLogARB");
char* vs;
char* fs;
GLhandleARB v = glCreateShaderObjectARB(GL_VERTEX_SHADER_ARB);
GLhandleARB f = glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
vs = textFileRead("vert.gl");
fs = textFileRead("frag.gl");
const char* vv = vs;
const char* ff = fs;
glShaderSourceARB(v, 1, (const GLcharARB**)&vv, NULL);
glShaderSourceARB(f, 1, (const GLcharARB**)&ff, NULL);
free(vs);
free(fs);
glCompileShaderARB(v);
glCompileShaderARB(f);
GLcharARB log[1024] = {0};
glGetInfoLogARB(v, 1024, NULL, log);
printf(log);
glGetInfoLogARB(f, 1024, NULL, log);
printf(log);
GLhandleARB p = glCreateProgramObjectARB();
glAttachObjectARB(p, v);
glAttachObjectARB(p, f);
glLinkProgramARB(p);
glUseProgramObjectARB(p);
}
void display(void)
{
static float r = 0;
r = (r > 360) ? (0) : (r += 0.1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotatef(r, 0, 1, 0);
glutSolidTeapot(1);
glPopMatrix();
glutSwapBuffers();
}
void reshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45, (float)w/(float)h, 1, 256);
gluLookAt(0, 0, 5, 0, 0, 0, 0, 1, 0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void idle(void)
{
glutPostRedisplay();
}
