1 files changed, 357 insertions, 0 deletions
diff --git a/progs/glsl/samplers.c b/progs/glsl/samplers.c
new file mode 100644
index 0000000000..d214009729
--- /dev/null
+++ b/progs/glsl/samplers.c
@@ -0,0 +1,357 @@
+/**
+ * Exercise all available GLSL texture samplers.
+ *
+ * Copyright (C) 2009  VMware, Inc.   All Rights Reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * We generate a fragment shader which uses the maximum number of supported
+ * texture samplers.
+ * For each sampler we create a separate texture.  Each texture has a
+ * single strip of color at a different intensity.  The fragment shader
+ * samples all the textures at the same coordinate and sums the values.
+ * The result should be a quad with rows of colors of increasing intensity
+ * from bottom to top.
+ *
+ * Brian Paul
+ * 1 Jan 2009
+ */
+
+#include <assert.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "GL/glut.h"
+#include "readtex.h"
+#include "extfuncs.h"
+#include "shaderutil.h"
+
+
+#define MAX_SAMPLERS 128
+
+
+static const char *Demo = "samplers";
+
+static GLuint Program;
+static GLint NumSamplers;
+static GLuint Textures[MAX_SAMPLERS];
+static GLfloat Xrot = 0.0, Yrot = .0, Zrot = 0.0;
+static GLfloat EyeDist = 10;
+static GLboolean Anim = GL_FALSE;
+
+
+static void
+DrawPolygon(GLfloat size)
+{
+   glPushMatrix();
+   glNormal3f(0, 0, 1);
+   glBegin(GL_POLYGON);
+
+   glMultiTexCoord2f(GL_TEXTURE0, 0, 0);
+   glVertex2f(-size, -size);
+
+   glMultiTexCoord2f(GL_TEXTURE0, 1, 0);
+   glVertex2f( size, -size);
+
+   glMultiTexCoord2f(GL_TEXTURE0, 1, 1);
+   glVertex2f( size,  size);
+
+   glMultiTexCoord2f(GL_TEXTURE0, 0, 1);
+   glVertex2f(-size,  size);
+
+   glEnd();
+   glPopMatrix();
+}
+
+
+static void
+draw(void)
+{
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+   glPushMatrix();
+      glTranslatef(0.0, 0.0, -EyeDist);
+      glRotatef(Zrot, 0, 0, 1);
+      glRotatef(Yrot, 0, 1, 0);
+      glRotatef(Xrot, 1, 0, 0);
+
+      DrawPolygon(3.0);
+
+   glPopMatrix();
+
+   glutSwapBuffers();
+}
+
+
+static void
+idle(void)
+{
+   GLfloat t = 0.05 * glutGet(GLUT_ELAPSED_TIME);
+   Yrot = t;
+   glutPostRedisplay();
+}
+
+
+static void
+key(unsigned char k, int x, int y)
+{
+   (void) x;
+   (void) y;
+   switch (k) {
+   case ' ':
+   case 'a':
+      Anim = !Anim;
+      if (Anim)
+         glutIdleFunc(idle);
+      else
+         glutIdleFunc(NULL);
+      break;
+   case 'z':
+      EyeDist -= 0.5;
+      if (EyeDist < 3.0)
+         EyeDist = 3.0;
+      break;
+   case 'Z':
+      EyeDist += 0.5;
+      if (EyeDist > 90.0)
+         EyeDist = 90;
+      break;
+   case 27:
+      exit(0);
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+specialkey(int key, int x, int y)
+{
+   GLfloat step = 2.0;
+   (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();
+}
+
+
+/* new window size or exposure */
+static void
+Reshape(int width, int height)
+{
+   GLfloat ar = (float) width / (float) height;
+   glViewport(0, 0, (GLint)width, (GLint)height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustum(-2.0*ar, 2.0*ar, -2.0, 2.0, 4.0, 100.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+}
+
+
+static void
+InitTextures(void)
+{
+   const GLint size = MAX_SAMPLERS;
+   GLubyte *texImage;
+   GLenum filter = GL_NEAREST;
+   GLint stripeSize;
+   GLint s;
+
+   texImage = (GLubyte *) malloc(size * size * 4);
+
+   glGenTextures(NumSamplers, Textures);
+
+   /* size of texels stripe */
+   stripeSize = size / NumSamplers;
+
+   /* create a texture for each sampler */
+   for (s = 0; s < NumSamplers; s++) {
+      GLint x, y, ypos;
+      GLubyte intensity = 31 + s * (256-32) / (NumSamplers - 1);
+
+      printf("Texture %d: color = %d, %d, %d\n", s,
+             (int) intensity, 0, (int) intensity );
+
+      /* initialize the texture to black */
+      memset(texImage, 0, size * size * 4);
+
+      /* set a stripe of texels to the intensity value */
+      ypos = s * stripeSize;
+      for (y = 0; y < stripeSize; y++) {
+         for (x = 0; x < size; x++) {
+            GLint k = 4 * ((ypos + y) * size + x);
+            texImage[k + 0] = intensity;
+            texImage[k + 1] = intensity;
+            texImage[k + 2] = 0;
+            texImage[k + 3] = 255;
+         }
+      }
+
+      glActiveTexture(GL_TEXTURE0 + s);
+      glBindTexture(GL_TEXTURE_2D, Textures[s]);
+      gluBuild2DMipmaps(GL_TEXTURE_2D, 4, size, size,
+                        GL_RGBA, GL_UNSIGNED_BYTE, texImage);
+     
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
+   }
+
+   free(texImage);
+}
+
+
+/**
+ * Generate a fragment shader that uses the given number of samplers.
+ */
+static char *
+GenFragmentShader(GLint numSamplers)
+{
+   const int maxLen = 10 * 1000;
+   char *prog = (char *) malloc(maxLen);
+   char *p = prog;
+   int s;
+
+   p += sprintf(p, "// Generated fragment shader:\n");
+   for (s = 0; s < numSamplers; s++) {
+      p += sprintf(p, "uniform sampler2D tex%d;\n", s);
+   }
+   p += sprintf(p, "void main()\n");
+   p += sprintf(p, "{\n");
+   p += sprintf(p, "   vec4 color = vec4(0.0);\n");
+   for (s = 0; s < numSamplers; s++) {
+      p += sprintf(p, "   color += texture2D(tex%d, gl_TexCoord[0].xy);\n", s);
+   }
+   p += sprintf(p, "   gl_FragColor = color;\n");
+   p += sprintf(p, "}\n");
+
+   assert(p - prog < maxLen);
+   return prog;
+}
+
+
+/** Create & bind shader program */
+static GLuint
+CreateProgram(void)
+{
+   GLuint fragShader, vertShader, program;
+   const char *vertShaderText = 
+      "void main() \n"
+      "{ \n"
+      "   gl_TexCoord[0] = gl_MultiTexCoord0; \n"
+      "   gl_Position = ftransform(); \n"
+      "} \n";
+   char *fragShaderText = GenFragmentShader(NumSamplers);
+
+   printf("%s", fragShaderText);
+
+   vertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText);
+   fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText);
+   assert(vertShader);
+   program = LinkShaders(vertShader, fragShader);
+
+   glUseProgram_func(program);
+
+   free(fragShaderText);
+
+   return program;
+}
+
+
+static void
+InitProgram(void)
+{
+   GLint s;
+
+   Program = CreateProgram();
+
+   /* init sampler uniforms */
+   for (s = 0; s < NumSamplers; s++) {
+      char uname[10];
+      GLint loc;
+
+      sprintf(uname, "tex%d", s);
+      loc = glGetUniformLocation_func(Program, uname);
+      assert(loc >= 0);
+
+      glUniform1i_func(loc, s);
+   }
+}
+
+
+static void
+InitGL(void)
+{
+   if (!ShadersSupported()) {
+      printf("GLSL not supported!\n");
+      exit(1);
+   }
+
+   printf("GL_RENDERER = %s\n", (const char *) glGetString(GL_RENDERER));
+
+   GetExtensionFuncs();
+
+   glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &NumSamplers);
+   if (NumSamplers > MAX_SAMPLERS)
+      NumSamplers = MAX_SAMPLERS;
+   printf("Testing %d samplers\n", NumSamplers);
+
+   InitTextures();
+   InitProgram();
+
+   glClearColor(.6, .6, .9, 0);
+   glColor3f(1.0, 1.0, 1.0);
+
+   printf("Each color corresponds to a separate sampler/texture.\n");
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowSize(500, 400);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
+   glutCreateWindow(Demo);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(key);
+   glutSpecialFunc(specialkey);
+   glutDisplayFunc(draw);
+   if (Anim)
+      glutIdleFunc(idle);
+   InitGL();
+   glutMainLoop();
+   return 0;
+}