Demonstrate GLSL fragment and vertex shaders.

2 files changed, 286 insertions, 0 deletions

diff --git a/progs/demos/Makefile b/progs/demos/Makefile
index 2009c42c69..39674b0ce2 100644
--- a/progs/demos/Makefile
+++ b/progs/demos/Makefile
@@ -15,6 +15,7 @@ LIB_DEP = $(LIB_DIR)/$(GL_LIB_NAME) $(LIB_DIR)/$(GLU_LIB_NAME) $(LIB_DIR)/$(GLUT
 
 PROGS = \
 	arbfplight \
+	arbfslight \
 	arbocclude \
 	bounce \
 	clearspd \
diff --git a/progs/demos/arbfslight.c b/progs/demos/arbfslight.c
new file mode 100644
index 0000000000..e5cfadc991
--- /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;
+}
+