Clean up the fbo component, fix related issues

1 files changed, 87 insertions, 0 deletions

diff --git a/tests/fbo.cc b/tests/fbo.cc
new file mode 100644
index 0000000..2c7abb4
--- /dev/null
+++ b/tests/fbo.cc
@@ -0,0 +1,87 @@
+#include "fbo.h"
+#include <stdio.h>
+#include <iostream>
+
+fbo_t *fbo_new()
+{
+  fbo_t *fbo = new fbo_t;
+  fbo->fbo_id = 0;
+  fbo->old_fbo_id = 0;
+  fbo->renderbuf_id = 0;
+  fbo->depthbuf_id = 0;
+
+  return fbo;
+}
+
+#define REPORTGLERROR(task) { GLenum tGLErr = glGetError(); if (tGLErr != GL_NO_ERROR) { std::cout << "OpenGL error " << tGLErr << " while " << task << "\n"; } }
+
+bool fbo_init(fbo_t *fbo, size_t width, size_t height)
+{
+  if (!glewIsSupported("GL_ARB_framebuffer_object")) {
+    fprintf(stderr, "Framebuffer extension not found\n");
+    return false;
+  }
+
+  // Generate and bind FBO
+  glGenFramebuffersEXT(1, &fbo->fbo_id);
+  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo->fbo_id);
+  REPORTGLERROR("binding framebuffer");
+
+  // Generate depth and render buffers
+  glGenRenderbuffersEXT(1, &fbo->depthbuf_id);
+  glGenRenderbuffersEXT(1, &fbo->renderbuf_id);
+
+  // Create buffers with correct size
+  if (!fbo_resize(fbo, width, height)) return false;
+
+  // Attach render and depth buffers
+  glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, 
+                               GL_RENDERBUFFER_EXT, fbo->renderbuf_id);
+  REPORTGLERROR("specifying color render buffer");
+
+  if (glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) != GL_FRAMEBUFFER_COMPLETE_EXT) {
+    fprintf(stderr, "Problem with OpenGL framebuffer after specifying color render buffer.\n");
+    return false;
+  }
+
+  glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, 
+                               GL_RENDERBUFFER_EXT, fbo->depthbuf_id);
+  REPORTGLERROR("specifying depth render buffer");
+
+  if (glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) != GL_FRAMEBUFFER_COMPLETE_EXT) {
+    fprintf(stderr, "Problem with OpenGL framebuffer after specifying depth render buffer.\n");
+    return false;
+  }
+
+  return true;
+}
+
+bool fbo_resize(fbo_t *fbo, size_t width, size_t height)
+{
+  glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo->depthbuf_id);
+  glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
+  REPORTGLERROR("creating depth render buffer");
+
+  glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo->renderbuf_id);
+  glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGBA8, width, height);
+  REPORTGLERROR("creating color render buffer");
+
+  return true;
+}
+
+void fbo_delete(fbo_t *fbo)
+{
+  delete fbo;
+}
+
+GLuint fbo_bind(fbo_t *fbo)
+{
+  glGetIntegerv(GL_FRAMEBUFFER_BINDING, (GLint *)&fbo->old_fbo_id);
+  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo->fbo_id);
+  return fbo->old_fbo_id;
+}
+
+void fbo_unbind(fbo_t *fbo)
+{
+  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo->old_fbo_id);
+}