progs/tests: added test for GL_EXT_draw_buffers2

Render into two color buffers (render targets).  Display half of each
buffer in the window.  Use different color masks for each render target.
Only enable blending for the second render target.

progs/tests/Makefile

@@ -42,6 +42,7 @@ SOURCES = \
 	crossbar.c \
 	cva.c \
 	drawbuffers.c \
+	drawbuffers2.c \
 	exactrast.c \
 	ext422square.c \
 	floattex.c \

progs/tests/SConscript

@@ -64,6 +64,7 @@ progs = [
     'crossbar',
     'cva',
     'drawbuffers',
+    'drawbuffers2',
     'exactrast',
     'ext422square',
     'fbotest1',

progs/tests/drawbuffers2.c

@@ -0,0 +1,364 @@
+/*
+ * Test GL_ARB_draw_buffers2, GL_ARB_draw_buffers, GL_EXT_framebuffer_object
+ * and GLSL's gl_FragData[].
+ *
+ * We draw to two color buffers and show the left half of the first
+ * color buffer on the left side of the window, and show the right
+ * half of the second color buffer on the right side of the window.
+ *
+ * Different color masks are used for the two color buffers.
+ * Blending is enabled for the second buffer only.
+ *
+ * Brian Paul
+ * 31 Dec 2009
+ */
+
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glew.h>
+#include <GL/glut.h>
+#include "extfuncs.h"
+
+static int Win;
+static int Width = 400, Height = 400;
+static GLuint FBobject, RBobjects[3];
+static GLfloat Xrot = 0.0, Yrot = 0.0;
+static GLuint Program;
+static GLboolean Anim = GL_TRUE;
+
+
+static void
+CheckError(int line)
+{
+   GLenum err = glGetError();
+   if (err) {
+      printf("GL Error 0x%x at line %d\n", (int) err, line);
+   }
+}
+
+
+static void
+Display(void)
+{
+   GLubyte *buffer = malloc(Width * Height * 4);
+   static const GLenum buffers[2] = {
+      GL_COLOR_ATTACHMENT0_EXT,
+      GL_COLOR_ATTACHMENT1_EXT
+   };
+
+   glUseProgram_func(Program);
+
+   glEnable(GL_DEPTH_TEST);
+
+   /* draw to user framebuffer */
+   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, FBobject);
+
+   /* Clear color buffer 0 (blue) */
+   glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
+   glClear(GL_COLOR_BUFFER_BIT);
+
+   /* Clear color buffer 1 (1 - blue) */
+   glDrawBuffer(GL_COLOR_ATTACHMENT1_EXT);
+   glClear(GL_COLOR_BUFFER_BIT);
+
+   glClear(GL_DEPTH_BUFFER_BIT);
+
+   /* draw to two buffers w/ fragment shader */
+   glDrawBuffersARB(2, buffers);
+
+   /* different color masks for each buffer */
+   if (1) {
+   glColorMaskIndexedEXT(0, GL_TRUE, GL_FALSE, GL_FALSE, GL_FALSE);
+   glColorMaskIndexedEXT(1, GL_FALSE, GL_TRUE, GL_FALSE, GL_FALSE);
+   }
+
+   glPushMatrix();
+   glRotatef(Xrot, 1, 0, 0);
+   glRotatef(Yrot, 0, 1, 0);
+   glPushMatrix();
+   glTranslatef(1, 0, 0);
+   glutSolidTorus(1.0, 2.0, 10, 20);
+   glPopMatrix();
+   glPushMatrix();
+   glTranslatef(-1, 0, 0);
+   glRotatef(90, 1, 0, 0);
+   glutSolidTorus(1.0, 2.0, 10, 20);
+   glPopMatrix();
+   glPopMatrix();
+
+   /* restore default color masks */
+   glColorMaskIndexedEXT(0, GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+   glColorMaskIndexedEXT(1, GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+
+   /* read from user framebuffer */
+   /* left half = colorbuffer 0 */
+   glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
+   glPixelStorei(GL_PACK_ROW_LENGTH, Width);
+   glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
+   glReadPixels(0, 0, Width / 2, Height, GL_RGBA, GL_UNSIGNED_BYTE,
+                buffer);
+
+   /* right half = colorbuffer 1 */
+   glReadBuffer(GL_COLOR_ATTACHMENT1_EXT);
+   glPixelStorei(GL_PACK_SKIP_PIXELS, Width / 2);
+   glReadPixels(Width / 2, 0, Width - Width / 2, Height,
+                GL_RGBA, GL_UNSIGNED_BYTE,
+                buffer);
+
+   /* draw to window */
+   glUseProgram_func(0);
+   glDisable(GL_DEPTH_TEST);
+   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+   glWindowPos2iARB(0, 0);
+   glDrawPixels(Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
+
+   free(buffer);
+   glutSwapBuffers();
+   CheckError(__LINE__);
+}
+
+
+static void
+Idle(void)
+{
+   Xrot = glutGet(GLUT_ELAPSED_TIME) * 0.05;
+   glutPostRedisplay();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+   float ar = (float) width / (float) height;
+
+   glViewport(0, 0, width, height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustum(-ar, ar, -1.0, 1.0, 5.0, 35.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+   glTranslatef(0.0, 0.0, -20.0);
+
+   Width = width;
+   Height = height;
+
+   glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, RBobjects[0]);
+   glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
+   glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, RBobjects[1]);
+   glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
+   glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, RBobjects[2]);
+   glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT,
+                            Width, Height);
+}
+
+
+static void
+CleanUp(void)
+{
+   glDeleteFramebuffersEXT(1, &FBobject);
+   glDeleteRenderbuffersEXT(3, RBobjects);
+   glutDestroyWindow(Win);
+   exit(0);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+   (void) x;
+   (void) y;
+   switch (key) {
+   case ' ':
+      Anim = !Anim;
+      glutIdleFunc(Anim ? Idle : NULL);
+      break;
+   case 'x':
+      Xrot += 5.0;
+      break;
+   case 'X':
+      Xrot -= 5.0;
+      break;
+   case 'y':
+      Yrot += 5.0;
+      break;
+   case 'Y':
+      Yrot -= 5.0;
+      break;
+   case 27:
+      CleanUp();
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+CheckExtensions(void)
+{
+   const char *req[] = {
+      "GL_EXT_framebuffer_object",
+      "GL_ARB_draw_buffers",
+      "GL_EXT_draw_buffers2"
+   };
+
+   const char *version = (const char *) glGetString(GL_VERSION);
+   GLint numBuf;
+   GLint i;
+
+   for (i = 0; i < 3; i++) {
+      if (!glutExtensionSupported(req[i])) {
+         printf("Sorry, %s extension is required!\n", req[i]);
+         exit(1);
+      }
+   }
+   if (version[0] != '2') {
+      printf("Sorry, OpenGL 2.0 is required!\n");
+      exit(1);
+   }
+
+   glGetIntegerv(GL_MAX_DRAW_BUFFERS_ARB, &numBuf);
+   printf("GL_MAX_DRAW_BUFFERS_ARB = %d\n", numBuf);
+   if (numBuf < 2) {
+      printf("Sorry, GL_MAX_DRAW_BUFFERS_ARB needs to be >= 2\n");
+      exit(1);
+   }
+
+   printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
+}
+
+
+static void
+SetupRenderbuffers(void)
+{
+   glGenFramebuffersEXT(1, &FBobject);
+   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, FBobject);
+
+   glGenRenderbuffersEXT(3, RBobjects);
+
+   glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, RBobjects[0]);
+   glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
+
+   glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, RBobjects[1]);
+   glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
+
+   glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, RBobjects[2]);
+   glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT,
+                            Width, Height);
+
+   glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
+                                GL_RENDERBUFFER_EXT, RBobjects[0]);
+   glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT1_EXT,
+                                GL_RENDERBUFFER_EXT, RBobjects[1]);
+   glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
+                                GL_RENDERBUFFER_EXT, RBobjects[2]);
+
+   CheckError(__LINE__);
+}
+
+
+static GLuint
+LoadAndCompileShader(GLenum target, const char *text)
+{
+   GLint stat;
+   GLuint shader = glCreateShader_func(target);
+   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, "drawbuffers: problem compiling shader:\n%s\n", log);
+      exit(1);
+   }
+   return shader;
+}
+
+
+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, "drawbuffers: shader link error:\n%s\n", log);
+   }
+}
+
+
+static void
+SetupShaders(void)
+{
+   /* emit same color to both draw buffers */
+   static const char *fragShaderText =
+      "void main() {\n"
+      "   gl_FragData[0] = gl_Color; \n"
+      "   gl_FragData[1] = gl_Color; \n"
+      "}\n";
+
+   GLuint fragShader;
+
+   fragShader = LoadAndCompileShader(GL_FRAGMENT_SHADER, fragShaderText);
+   Program = glCreateProgram_func();
+
+   glAttachShader_func(Program, fragShader);
+   glLinkProgram_func(Program);
+   CheckLink(Program);
+   glUseProgram_func(Program);
+}
+
+
+static void
+SetupLighting(void)
+{
+   static const GLfloat ambient[4] = { 0.0, 0.0, 0.0, 0.0 };
+   static const GLfloat diffuse[4] = { 1.0, 1.0, 1.0, 0.75 };
+
+   glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambient);
+   glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, ambient);
+   glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, diffuse);
+
+   glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, 0);
+   glEnable(GL_LIGHT0);
+   glEnable(GL_LIGHTING);
+}
+
+
+static void
+Init(void)
+{
+   CheckExtensions();
+   GetExtensionFuncs();
+   SetupRenderbuffers();
+   SetupShaders();
+   SetupLighting();
+   glEnable(GL_DEPTH_TEST);
+
+   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+   glEnableIndexedEXT(GL_BLEND, 1);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowPosition(0, 0);
+   glutInitWindowSize(Width, Height);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
+   Win = glutCreateWindow(argv[0]);
+   glewInit();
+   glutIdleFunc(Anim ? Idle : NULL);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutDisplayFunc(Display);
+   Init();
+   glutMainLoop();
+   return 0;
+}