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#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)
{
}
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