1 files changed, 114 insertions, 0 deletions
diff --git a/tests/OffscreenContext.cc b/tests/OffscreenContext.cc
new file mode 100644
index 0000000..fa1afde
--- /dev/null
+++ b/tests/OffscreenContext.cc
@@ -0,0 +1,114 @@
+#include "OffscreenContext.h"
+#include "printutils.h"
+#include "imageutils.h"
+
+// see http://www.gamedev.net/topic/552607-conflict-between-glew-and-sdl/
+#define NO_SDL_GLEXT
+#include <GL/glew.h>
+
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glext.h>
+
+//#include <GL/gl.h>
+//#include <GL/glu.h>      // for gluCheckExtension
+#include <SDL.h>
+
+struct OffscreenContext
+{
+  int width;
+  int height;
+  GLuint fbo;
+  GLuint colorbo;
+  GLuint depthbo;
+};
+
+void write_targa(const char *filename, GLubyte *pixels, int width, int height)
+{
+	FILE *f = fopen( filename, "w" );
+	int y;
+	if (f) {
+		GLubyte header[] = {
+			00,00,02, 00,00,00, 00,00,00, 00,00,00,
+			0xff & width, 0xff & width >> 8,
+			0xff & height, 0xff & height >> 8,
+			32, 0x20 }; // next-to-last = bit depth
+		fwrite( header, sizeof(header), 1, f);
+		for (y=height-1; y>=0; y--)
+			fwrite( pixels + y*width*4, 4, width, f);
+		fclose(f);
+	}
+}
+
+OffscreenContext *create_offscreen_context(int w, int h)
+{
+  OffscreenContext *ctx = new OffscreenContext;
+  ctx->width = w;
+  ctx->height = h;
+
+  // dummy window 
+  SDL_Init(SDL_INIT_VIDEO);
+  SDL_SetVideoMode(ctx->width,ctx->height,32,SDL_OPENGL);
+
+  // must come after openGL context init (done by dummy window)
+  // but must also come before various EXT calls
+  //glewInit();
+
+/*
+	glClearColor(1, 1, 1, 1);
+	glClear(GL_COLOR_BUFFER_BIT);
+	glBegin(GL_TRIANGLES);
+	glColor3f( 1, 0, 0);
+	glVertex3f( 0, 0, 0);
+	glVertex3f( 1, 0, 0);
+	glVertex3f( 0, 1, 0);
+	glEnd();
+        SDL_GL_SwapBuffers();
+//  sleep(2);
+*/
+
+  int samplesPerPixel = 4; // R, G, B and A
+
+/*  char * filename = "blah.tga";
+  GLubyte pixels[ ctx->width * ctx->height * samplesPerPixel ];
+  glReadPixels(0, 0, ctx->width, ctx->height, GL_BGRA, GL_UNSIGNED_BYTE, pixels);
+  printf("writing %s\n",filename);
+  write_targa(filename,pixels,ctx->width, ctx->height);*/
+  return ctx;
+}
+
+bool teardown_offscreen_context(OffscreenContext *ctx)
+{
+  return true;
+}
+
+/*!
+  Capture framebuffer from OpenGL and write it to the given filename as PNG.
+*/
+bool save_framebuffer(OffscreenContext *ctx, const char *filename)
+{
+  SDL_GL_SwapBuffers(); // show image
+
+  int samplesPerPixel = 4; // R, G, B and A
+  GLubyte pixels[ctx->width * ctx->height * samplesPerPixel];
+  glReadPixels(0, 0, ctx->width, ctx->height, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+
+  // Flip it vertically - images read from OpenGL buffers are upside-down
+  int rowBytes = samplesPerPixel * ctx->width;
+  unsigned char *flippedBuffer = (unsigned char *)malloc(rowBytes * ctx->height);
+  if (!flippedBuffer) {
+    std::cout << "Unable to allocate flipped buffer for corrected image.";
+    return 1;
+  }
+  flip_image(pixels, flippedBuffer, samplesPerPixel, ctx->width, ctx->height);
+
+  bool writeok = write_png(filename, flippedBuffer, ctx->width, ctx->height);
+
+  free(flippedBuffer);
+
+  return writeok;
+}
+
+void bind_offscreen_context(OffscreenContext *ctx)
+{
+}