- static bool first = true;
- if (first) {
- glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, GL_UNSIGNED_BYTE, src);
- } else {
- glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, format, GL_UNSIGNED_BYTE, src);
- }
+ // Create PBO to hold the texture, and then the texture itself.
+ glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 2);
+ check_error();
+ glBufferData(GL_PIXEL_UNPACK_BUFFER_ARB, width * height * bytes_per_pixel, NULL, GL_STREAM_DRAW);
+ check_error();
+
+ void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
+ memset(mapped_pbo, 0, width * height * bytes_per_pixel);
+ glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
+
+ glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
+ check_error();
+ glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
+ check_error();
+ glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
+ check_error();
+
+ finalized = true;
+}
+
+void EffectChain::render_to_screen(unsigned char *src)
+{
+ assert(finalized);
+
+ // Copy the pixel data into the PBO.
+ glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 2);
+ check_error();
+ void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
+ memcpy(mapped_pbo, src, width * height * bytes_per_pixel);
+ glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
+ check_error();
+
+ // Re-upload the texture from the PBO.
+ glActiveTexture(GL_TEXTURE0);
+ check_error();
+ glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
+ check_error();
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, format, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
+ check_error();
+ glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
+ check_error();
+
+ glUseProgram(glsl_program_num);
+ check_error();
+