demos: add progs/glsl/shadow_sampler.c to test GLSL shadow2D(), etc.

Heh, I wrote this program a long time ago but just discovered today that
it wasn't in git.

2 files changed, 342 insertions, 0 deletions

diff --git a/progs/glsl/Makefile b/progs/glsl/Makefile
index 7099eeadbd..8061277033 100644
--- a/progs/glsl/Makefile
+++ b/progs/glsl/Makefile
@@ -25,6 +25,7 @@ PROGS = \
 	pointcoord \
 	samplers \
 	samplers_array \
+	shadow_sampler \
 	skinning \
 	texdemo1 \
 	toyball \
diff --git a/progs/glsl/shadow_sampler.c b/progs/glsl/shadow_sampler.c
new file mode 100644
index 0000000000..2902b53552
--- /dev/null
+++ b/progs/glsl/shadow_sampler.c
@@ -0,0 +1,341 @@
+/**
+ * Test shadow2DRectProj() and shadow2D() functions.
+ * Brian Paul
+ * 11 April 2007
+ */
+
+#define GL_GLEXT_PROTOTYPES
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/gl.h>
+#include <GL/glut.h>
+#include <GL/glext.h>
+#include "extfuncs.h"
+
+
+/** Use GL_RECTANGLE texture (with projective texcoords)? */
+#define USE_RECT 01
+
+#define TEXSIZE 16
+
+
+static char *FragProgFile = NULL;
+static char *VertProgFile = NULL;
+
+static GLuint fragShader;
+static GLuint vertShader;
+static GLuint program;
+
+static GLint uTexture2D;
+static GLint uTextureRect;
+
+static GLint win = 0;
+
+static GLenum Filter = GL_LINEAR;
+
+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);
+   }
+}
+
+
+static void
+PrintString(const char *s)
+{
+   while (*s) {
+      glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
+      s++;
+   }
+}
+
+
+static void
+Redisplay(void)
+{
+   CheckError(__LINE__);
+   glClear(GL_COLOR_BUFFER_BIT);
+
+   glPushMatrix();
+
+   CheckError(__LINE__);
+   glUseProgram_func(program);
+   CheckError(__LINE__);
+
+   glBegin(GL_POLYGON);
+#if USE_RECT
+   /* scale coords by two to test projection */
+   glTexCoord4f(        0,         0,   0, 2.0);  glVertex2f(-1, -1);
+   glTexCoord4f(2*TEXSIZE,         0, 2*1, 2.0);  glVertex2f( 1, -1);
+   glTexCoord4f(2*TEXSIZE, 2*TEXSIZE, 2*1, 2.0);  glVertex2f( 1,  1);
+   glTexCoord4f(        0, 2*TEXSIZE,   0, 2.0);  glVertex2f(-1,  1);
+#else
+   glTexCoord3f(0, 0, 0);  glVertex2f(-1, -1);
+   glTexCoord3f(1, 0, 1);  glVertex2f( 1, -1);
+   glTexCoord3f(1, 1, 1);  glVertex2f( 1,  1);
+   glTexCoord3f(0, 1, 0);  glVertex2f(-1,  1);
+#endif
+   glEnd();
+
+   glPopMatrix();
+
+   glUseProgram_func(0);
+   glWindowPos2iARB(80, 20);
+   PrintString("white   black   white   black");
+
+   glutSwapBuffers();
+}
+
+
+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, -8.0f);
+}
+
+
+static void
+CleanUp(void)
+{
+   glDeleteShader_func(fragShader);
+   glDeleteShader_func(vertShader);
+   glDeleteProgram_func(program);
+   glutDestroyWindow(win);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+  (void) x;
+  (void) y;
+
+   switch(key) {
+   case 27:
+      CleanUp();
+      exit(0);
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+MakeTexture(void)
+{
+   GLfloat image[TEXSIZE][TEXSIZE];
+   GLuint i, j;
+
+   for (i = 0; i < TEXSIZE; i++) {
+      for (j = 0; j < TEXSIZE; j++) {
+         if (j < (TEXSIZE / 2)) {
+            image[i][j] = 0.25;
+         }
+         else {
+            image[i][j] = 0.75;
+         }
+      }
+   }
+
+   glActiveTexture(GL_TEXTURE0); /* unit 0 */
+   glBindTexture(GL_TEXTURE_2D, 42);
+   glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, TEXSIZE, TEXSIZE, 0,
+                GL_DEPTH_COMPONENT, GL_FLOAT, image);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, Filter);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, Filter);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB,
+                   GL_COMPARE_R_TO_TEXTURE_ARB);
+   CheckError(__LINE__);
+
+   glActiveTexture(GL_TEXTURE1); /* unit 1 */
+   glBindTexture(GL_TEXTURE_RECTANGLE_ARB, 43);
+   glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_DEPTH_COMPONENT,
+                TEXSIZE, 10, 0,/*16x10*/
+                GL_DEPTH_COMPONENT, GL_FLOAT, image);
+   glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, Filter);
+   glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, Filter);
+   glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_COMPARE_MODE_ARB,
+                   GL_COMPARE_R_TO_TEXTURE_ARB);
+   CheckError(__LINE__);
+}
+
+
+static void
+LoadAndCompileShader(GLuint shader, const char *text)
+{
+   GLint stat;
+   glShaderSource_func(shader, 1, (const GLchar **) &text, NULL);
+   glCompileShader_func(shader);
+   glGetShaderiv_func(shader, GL_COMPILE_STATUS, &stat);
+   if (!stat) {
+      GLchar log[1000];
+      GLsizei len;
+      glGetShaderInfoLog_func(shader, 1000, &len, log);
+      fprintf(stderr, "fslight: problem compiling shader:\n%s\n", log);
+      exit(1);
+   }
+}
+
+
+/**
+ * Read a shader from a file.
+ */
+static void
+ReadShader(GLuint shader, const char *filename)
+{
+   const int max = 100*1000;
+   int n;
+   char *buffer = (char*) malloc(max);
+   FILE *f = fopen(filename, "r");
+   if (!f) {
+      fprintf(stderr, "fslight: Unable to open shader file %s\n", filename);
+      exit(1);
+   }
+
+   n = fread(buffer, 1, max, f);
+   printf("fslight: read %d bytes from shader file %s\n", n, filename);
+   if (n > 0) {
+      buffer[n] = 0;
+      LoadAndCompileShader(shader, buffer);
+   }
+
+   fclose(f);
+   free(buffer);
+}
+
+
+static void
+CheckLink(GLuint prog)
+{
+   GLint stat;
+   glGetProgramiv_func(prog, GL_LINK_STATUS, &stat);
+   if (!stat) {
+      GLchar log[1000];
+      GLsizei len;
+      glGetProgramInfoLog_func(prog, 1000, &len, log);
+      fprintf(stderr, "Linker error:\n%s\n", log);
+   }
+}
+
+
+static void
+Init(void)
+{
+   static const char *fragShaderText =
+      "uniform sampler2DShadow shadowTex2D; \n"
+      "uniform sampler2DRectShadow shadowTexRect; \n"
+      "void main() {\n"
+#if USE_RECT
+      "   gl_FragColor = shadow2DRectProj(shadowTexRect, gl_TexCoord[0]); \n"
+#else
+      "   gl_FragColor = shadow2D(shadowTex2D, gl_TexCoord[0].xyz); \n"
+#endif
+      "}\n";
+   static const char *vertShaderText =
+      "void main() {\n"
+      "   gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+      "   gl_TexCoord[0] = gl_MultiTexCoord0; \n"
+      "}\n";
+   const char *version;
+
+#if USE_RECT
+   if (!glutExtensionSupported("GL_ARB_texture_rectangle")) {
+      printf("This program requires GL_ARB_texture_rectangle\n");
+      exit(1);
+   }
+#endif
+
+   version = (const char *) glGetString(GL_VERSION);
+   if (version[0] != '2' || version[1] != '.') {
+      printf("This program requires OpenGL 2.x, found %s\n", version);
+      exit(1);
+   }
+   printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
+
+   GetExtensionFuncs();
+
+   fragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
+   if (FragProgFile)
+      ReadShader(fragShader, FragProgFile);
+   else
+      LoadAndCompileShader(fragShader, fragShaderText);
+
+   vertShader = glCreateShader_func(GL_VERTEX_SHADER);
+   if (VertProgFile)
+      ReadShader(vertShader, VertProgFile);
+   else
+      LoadAndCompileShader(vertShader, vertShaderText);
+
+   program = glCreateProgram_func();
+   glAttachShader_func(program, fragShader);
+   glAttachShader_func(program, vertShader);
+   glLinkProgram_func(program);
+   CheckLink(program);
+   glUseProgram_func(program);
+
+   uTexture2D = glGetUniformLocation_func(program, "shadowTex2D");
+   uTextureRect = glGetUniformLocation_func(program, "shadowTexRect");
+   printf("uTexture2D %d  uTextureRect %d\n", uTexture2D, uTextureRect);
+   if (uTexture2D >= 0) {
+      glUniform1i_func(uTexture2D, 0);  /* use texture unit 0 */
+   }
+   if (uTextureRect >= 0) {
+      glUniform1i_func(uTextureRect, 1);  /* use texture unit 0 */
+   }
+   CheckError(__LINE__);
+
+   glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
+   glColor3f(1, 1, 1);
+
+   MakeTexture();
+   CheckError(__LINE__);
+}
+
+
+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);
+   glutInitWindowPosition( 0, 0);
+   glutInitWindowSize(400, 300);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
+   win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutDisplayFunc(Redisplay);
+   ParseOptions(argc, argv);
+   Init();
+   glutMainLoop();
+   return 0;
+}
+
+