/* * Use GL_ARB_fragment_shader and GL_ARB_vertex_shader to implement * simple per-pixel lighting. * * Michal Krol * 20 February 2006 * * Based on the original demo by: * Brian Paul * 17 April 2003 */ #ifdef WIN32 #include <windows.h> #endif #include <stdio.h> #include <stdlib.h> #include <math.h> #include <GL/gl.h> #include <GL/glut.h> #include <GL/glext.h> #ifdef WIN32 #define GETPROCADDRESS wglGetProcAddress #else #define GETPROCADDRESS glutGetProcAddress #endif static GLfloat diffuse[4] = { 0.5f, 0.5f, 1.0f, 1.0f }; static GLfloat specular[4] = { 0.8f, 0.8f, 0.8f, 1.0f }; static GLfloat lightPos[4] = { 0.0f, 10.0f, 20.0f, 1.0f }; static GLfloat delta = 1.0f; static GLhandleARB fragShader; static GLhandleARB vertShader; static GLhandleARB program; static GLint uLightPos; static GLint uDiffuse; static GLint uSpecular; static GLboolean anim = GL_TRUE; static GLboolean wire = GL_FALSE; static GLboolean pixelLight = GL_TRUE; static GLint t0 = 0; static GLint frames = 0; static GLfloat xRot = 0.0f, yRot = 0.0f; static PFNGLCREATESHADEROBJECTARBPROC glCreateShaderObjectARB = NULL; static PFNGLSHADERSOURCEARBPROC glShaderSourceARB = NULL; static PFNGLCOMPILESHADERARBPROC glCompileShaderARB = NULL; static PFNGLCREATEPROGRAMOBJECTARBPROC glCreateProgramObjectARB = NULL; static PFNGLATTACHOBJECTARBPROC glAttachObjectARB = NULL; static PFNGLLINKPROGRAMARBPROC glLinkProgramARB = NULL; static PFNGLUSEPROGRAMOBJECTARBPROC glUseProgramObjectARB = NULL; static PFNGLGETUNIFORMLOCATIONARBPROC glGetUniformLocationARB = NULL; static PFNGLUNIFORM3FVARBPROC glUniform3fvARB = NULL; static PFNGLUNIFORM3FVARBPROC glUniform4fvARB = NULL; static void normalize (GLfloat *dst, const GLfloat *src) { GLfloat len = sqrtf (src[0] * src[0] + src[1] * src[1] + src[2] * src[2]); dst[0] = src[0] / len; dst[1] = src[1] / len; dst[2] = src[2] / len; } static void Redisplay (void) { glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); if (pixelLight) { GLfloat vec[3]; glUseProgramObjectARB (program); normalize (vec, lightPos); glUniform3fvARB (uLightPos, 1, vec); glDisable(GL_LIGHTING); } else { glUseProgramObjectARB (0); glLightfv (GL_LIGHT0, GL_POSITION, lightPos); glEnable(GL_LIGHTING); } glPushMatrix (); glRotatef (xRot, 1.0f, 0.0f, 0.0f); glRotatef (yRot, 0.0f, 1.0f, 0.0f); glutSolidSphere (2.0, 10, 5); glPopMatrix (); glutSwapBuffers(); frames++; if (anim) { GLint t = glutGet (GLUT_ELAPSED_TIME); if (t - t0 >= 5000) { GLfloat seconds = (GLfloat) (t - t0) / 1000.0f; GLfloat fps = frames / seconds; printf ("%d frames in %6.3f seconds = %6.3f FPS\n", frames, seconds, fps); t0 = t; frames = 0; } } } static void Idle (void) { lightPos[0] += delta; if (lightPos[0] > 25.0f || lightPos[0] < -25.0f) delta = -delta; glutPostRedisplay (); } 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 Key (unsigned char key, int x, int y) { (void) x; (void) y; switch (key) { case ' ': case 'a': anim = !anim; if (anim) glutIdleFunc (Idle); else glutIdleFunc (NULL); break; case 'x': lightPos[0] -= 1.0f; break; case 'X': lightPos[0] += 1.0f; break; case 'w': wire = !wire; if (wire) glPolygonMode (GL_FRONT_AND_BACK, GL_LINE); else glPolygonMode (GL_FRONT_AND_BACK, GL_FILL); break; case 'p': pixelLight = !pixelLight; if (pixelLight) printf ("Per-pixel lighting\n"); else printf ("Conventional lighting\n"); break; case 27: 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) { static const char *fragShaderText = "uniform vec3 lightPos;\n" "uniform vec4 diffuse;\n" "uniform vec4 specular;\n" "varying vec3 normal;\n" "void main () {\n" " // Compute dot product of light direction and normal vector\n" " float dotProd = max (dot (lightPos, normalize (normal)), 0.0);\n" " // Compute diffuse and specular contributions\n" " gl_FragColor = diffuse * dotProd + specular * pow (dotProd, 20.0);\n" "}\n" ; static const char *vertShaderText = "varying vec3 normal;\n" "void main () {\n" " gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n" " normal = gl_NormalMatrix * gl_Normal;\n" "}\n" ; if (!glutExtensionSupported ("GL_ARB_fragment_shader")) { printf ("Sorry, this demo requires GL_ARB_fragment_shader\n"); exit(1); } if (!glutExtensionSupported ("GL_ARB_shader_objects")) { printf ("Sorry, this demo requires GL_ARB_shader_objects\n"); exit(1); } if (!glutExtensionSupported ("GL_ARB_shading_language_100")) { printf ("Sorry, this demo requires GL_ARB_shading_language_100\n"); exit(1); } if (!glutExtensionSupported ("GL_ARB_vertex_shader")) { printf ("Sorry, this demo requires GL_ARB_vertex_shader\n"); exit(1); } glCreateShaderObjectARB = (PFNGLCREATESHADEROBJECTARBPROC) GETPROCADDRESS ("glCreateShaderObjectARB"); glShaderSourceARB = (PFNGLSHADERSOURCEARBPROC) GETPROCADDRESS ("glShaderSourceARB"); glCompileShaderARB = (PFNGLCOMPILESHADERARBPROC) GETPROCADDRESS ("glCompileShaderARB"); glCreateProgramObjectARB = (PFNGLCREATEPROGRAMOBJECTARBPROC) GETPROCADDRESS ("glCreateProgramObjectARB"); glAttachObjectARB = (PFNGLATTACHOBJECTARBPROC) GETPROCADDRESS ("glAttachObjectARB"); glLinkProgramARB = (PFNGLLINKPROGRAMARBPROC) GETPROCADDRESS ("glLinkProgramARB"); glUseProgramObjectARB = (PFNGLUSEPROGRAMOBJECTARBPROC) GETPROCADDRESS ("glUseProgramObjectARB"); glGetUniformLocationARB = (PFNGLGETUNIFORMLOCATIONARBPROC) GETPROCADDRESS ("glGetUniformLocationARB"); glUniform3fvARB = (PFNGLUNIFORM3FVARBPROC) GETPROCADDRESS ("glUniform3fvARB"); glUniform4fvARB = (PFNGLUNIFORM3FVARBPROC) GETPROCADDRESS ("glUniform4fvARB"); fragShader = glCreateShaderObjectARB (GL_FRAGMENT_SHADER_ARB); glShaderSourceARB (fragShader, 1, &fragShaderText, NULL); glCompileShaderARB (fragShader); vertShader = glCreateShaderObjectARB (GL_VERTEX_SHADER_ARB); glShaderSourceARB (vertShader, 1, &vertShaderText, NULL); glCompileShaderARB (vertShader); program = glCreateProgramObjectARB (); glAttachObjectARB (program, fragShader); glAttachObjectARB (program, vertShader); glLinkProgramARB (program); glUseProgramObjectARB (program); uLightPos = glGetUniformLocationARB (program, "lightPos"); uDiffuse = glGetUniformLocationARB (program, "diffuse"); uSpecular = glGetUniformLocationARB (program, "specular"); glUniform4fvARB (uDiffuse, 1, diffuse); glUniform4fvARB (uSpecular, 1, specular); glClearColor (0.3f, 0.3f, 0.3f, 0.0f); glEnable (GL_DEPTH_TEST); glEnable (GL_LIGHT0); glEnable (GL_LIGHTING); glMaterialfv (GL_FRONT_AND_BACK, GL_DIFFUSE, diffuse); glMaterialfv (GL_FRONT_AND_BACK, GL_SPECULAR, specular); glMaterialf (GL_FRONT_AND_BACK, GL_SHININESS, 20.0f); printf ("GL_RENDERER = %s\n", (const char *) glGetString (GL_RENDERER)); printf ("Press p to toggle between per-pixel and per-vertex lighting\n"); } int main (int argc, char *argv[]) { glutInit (&argc, argv); glutInitWindowPosition ( 0, 0); glutInitWindowSize (200, 200); glutInitDisplayMode (GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH); glutCreateWindow (argv[0]); glutReshapeFunc (Reshape); glutKeyboardFunc (Key); glutSpecialFunc (SpecialKey); glutDisplayFunc (Redisplay); if (anim) glutIdleFunc (Idle); Init (); glutMainLoop (); return 0; }