Demonstrate GLSL fragment and vertex shaders.
diff --git a/progs/demos/Makefile b/progs/demos/Makefile
index 2009c42..39674b0 100644
--- a/progs/demos/Makefile
+++ b/progs/demos/Makefile
@@ -15,6 +15,7 @@
PROGS = \
arbfplight \
+ arbfslight \
arbocclude \
bounce \
clearspd \
diff --git a/progs/demos/arbfslight.c b/progs/demos/arbfslight.c
new file mode 100644
index 0000000..e5cfadc
--- /dev/null
+++ b/progs/demos/arbfslight.c
@@ -0,0 +1,285 @@
+/*
+ * Use GL_ARB_fragment_shader and GL_ARB_vertex_shader to implement
+ * simple per-pixel lighting.
+ *
+ * Michal Krol
+ * 14 February 2006
+ *
+ * Based on the original demo by:
+ * Brian Paul
+ * 17 April 2003
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <GL/glut.h>
+
+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 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 void Redisplay (void)
+{
+ glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+ if (pixelLight)
+ {
+ glUseProgramObjectARB (program);
+ /* XXX source from uniform lightPos */
+ glTexCoord4fv (lightPos);
+ 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 =
+ "void main () {\n"
+
+ /* XXX source from uniform lightPos */
+ " vec4 lightPos;\n"
+ " lightPos = gl_TexCoord[1];\n"
+
+ /* XXX source from uniform diffuse */
+ " vec4 diffuse;\n"
+ " diffuse.xy = vec2 (0.5);\n"
+ " diffuse.zw = vec2 (1.0);\n"
+
+ /* XXX source from uniform specular */
+ " vec4 specular;\n"
+ " specular.xyz = vec3 (0.8);\n"
+ " specular.w = 1.0;\n"
+
+ " // Compute normalized light direction\n"
+ " vec4 lightDir;\n"
+ " lightDir = lightPos / length (lightPos);\n"
+ " // Compute normalized normal\n"
+ " vec4 normal;\n"
+ " normal = gl_TexCoord[0] / length (gl_TexCoord[0]);\n"
+ " // Compute dot product of light direction and normal vector\n"
+ " float dotProd;\n"
+ " dotProd = clamp (dot (lightDir.xyz, normal.xyz), 0.0, 1.0);\n"
+ " // Compute diffuse and specular contributions\n"
+ " gl_FragColor = diffuse * dotProd + specular * pow (dotProd, 20.0);\n"
+ "}\n"
+ ;
+ static const char *vertShaderText =
+ "void main () {\n"
+ " gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+ " gl_TexCoord[0].xyz = gl_NormalMatrix * gl_Normal;\n"
+ " gl_TexCoord[0].w = 1.0;\n"
+
+ /* XXX source from uniform lightPos */
+ " gl_TexCoord[1] = gl_MultiTexCoord0;\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) glutGetProcAddress ("glCreateShaderObjectARB");
+ glShaderSourceARB = (PFNGLSHADERSOURCEARBPROC) glutGetProcAddress ("glShaderSourceARB");
+ glCompileShaderARB = (PFNGLCOMPILESHADERARBPROC) glutGetProcAddress ("glCompileShaderARB");
+ glCreateProgramObjectARB = (PFNGLCREATEPROGRAMOBJECTARBPROC) glutGetProcAddress ("glCreateProgramObjectARB");
+ glAttachObjectARB = (PFNGLATTACHOBJECTARBPROC) glutGetProcAddress ("glAttachObjectARB");
+ glLinkProgramARB = (PFNGLLINKPROGRAMARBPROC) glutGetProcAddress ("glLinkProgramARB");
+ glUseProgramObjectARB = (PFNGLUSEPROGRAMOBJECTARBPROC) glutGetProcAddress ("glUseProgramObjectARB");
+
+ 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);
+
+ 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;
+}
+