Merge pull request #186 from Wargus/tim/fix-screenshots-with-shaders

Fixes for screenshot code with opengl

src/include/shaders.h

@@ -2,8 +2,14 @@
 #define __SHADERS_H__
 #ifdef USE_OPENGL
 #define MAX_SHADERS 5
+#ifndef __APPLE__
+extern PFNGLBINDFRAMEBUFFEREXTPROC glBindFramebuffer;
+#else
+#define glBindFramebuffer glBindFramebufferEXT
+#endif
+extern GLuint fullscreenFramebuffer;
 extern unsigned ShaderIndex;
-extern void LoadShaders();
+extern bool LoadShaders();
 extern bool LoadShaderExtensions();
 extern void SetupFramebuffer();
 extern void RenderFramebufferToScreen();

src/video/png.cpp

@@ -318,7 +318,19 @@ void SaveScreenshotPNG(const char *name)
 	/* set up the output control if you are using standard C streams */
 	png_init_io(png_ptr, fp);
 
-	png_set_IHDR(png_ptr, info_ptr, Video.Width, Video.Height, 8,
+	int pngw, pngh;
+#if defined(USE_OPENGL) || defined(USE_GLES)
+	if (UseOpenGL) {
+		pngw = Video.ViewportWidth;
+		pngh = Video.ViewportHeight;
+	}
+	else
+#endif
+	{
+		pngw = Video.Width;
+		pngh = Video.Height;
+	}
+	png_set_IHDR(png_ptr, info_ptr, pngw, pngh, 8,
 				 PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
 				 PNG_FILTER_TYPE_DEFAULT);
 
@@ -328,15 +340,23 @@ void SaveScreenshotPNG(const char *name)
 
 #if defined(USE_OPENGL) || defined(USE_GLES)
 	if (UseOpenGL) {
-		std::vector<unsigned char> pixels;
-		pixels.resize(Video.Width * Video.Height * 3);
+		unsigned char* pixels = new unsigned char[Video.ViewportWidth * Video.ViewportHeight * 3];
+		if (GLShaderPipelineSupported) {
+			// switch to real display
+			glBindFramebuffer(GL_FRAMEBUFFER_EXT, 0);
+		}
 #ifdef USE_OPENGL
 		glReadBuffer(GL_FRONT);
 #endif
-		glReadPixels(0, 0, Video.Width, Video.Height, GL_RGB, GL_UNSIGNED_BYTE, &pixels[0]);
-		for (int i = 0; i < Video.Height; ++i) {
-			png_write_row(png_ptr, &pixels[(Video.Height - 1 - i) * Video.Width * 3]);
+		glReadPixels(0, 0, Video.ViewportWidth, Video.ViewportHeight, GL_RGB, GL_UNSIGNED_BYTE, pixels);
+		if (GLShaderPipelineSupported) {
+			// switch back to framebuffer
+			glBindFramebuffer(GL_FRAMEBUFFER_EXT, fullscreenFramebuffer);
 		}
+		for (int i = 0; i < Video.Height; ++i) {
+			png_write_row(png_ptr, &pixels[(Video.ViewportHeight - 1 - i) * Video.ViewportWidth * 3]);
+		}
+		delete []pixels;
 	} else
 #endif
 	{

src/video/shaders.cpp

@@ -394,27 +394,59 @@ void printProgramInfoLog(GLuint obj, const char* prefix)
 
 unsigned ShaderIndex = 0;
 
-extern void LoadShaders() {
+extern bool LoadShaders() {
 	GLuint vs, fs;
+	GLint params;
 	fs = glCreateShader(GL_FRAGMENT_SHADER);
+	if (fs == 0) {
+	    return false;
+	}
 	glShaderSource(fs, 1, (const char**)&(fragment_shaders[ShaderIndex]), NULL);
 	glCompileShader(fs);
+	glGetShaderiv(fs, GL_COMPILE_STATUS, &params);
+	if (params == GL_FALSE) {
+		glDeleteShader(fs);
+		return false;
+	}
 	//printShaderInfoLog(fs, "Fragment Shader");
 	ShaderIndex = (ShaderIndex + 1) % MAX_SHADERS;
 	vs = glCreateShader(GL_VERTEX_SHADER);
+	if (fs == 0) {
+	    glDeleteShader(fs);
+	    return false;
+	}
 	glShaderSource(vs, 1, (const char**)&vertex_shader, NULL);
 	glCompileShader(vs);
+	glGetShaderiv(fs, GL_COMPILE_STATUS, &params);
+	if (params == GL_FALSE) {
+		glDeleteShader(fs);
+		glDeleteShader(vs);
+		return false;
+	}
 	//printShaderInfoLog(vs, "Vertex Shader");
 	if (glIsProgram(fullscreenShader)) {
 		glDeleteProgram(fullscreenShader);
 	}
 	fullscreenShader = glCreateProgram();
+	if (fullscreenShader == 0) {
+		glDeleteShader(fs);
+		glDeleteShader(vs);
+		return false;
+	}
 	glAttachShader(fullscreenShader, vs);
 	glAttachShader(fullscreenShader, fs);
 	glLinkProgram(fullscreenShader);
+	glGetProgramiv(fullscreenShader, GL_LINK_STATUS, &params);
+	if (params == GL_FALSE) {
+		glDeleteShader(fs);
+		glDeleteShader(vs);
+		glDeleteProgram(fullscreenShader);
+		return false;
+	}
 	glDeleteShader(fs);
 	glDeleteShader(vs);
 	//printProgramInfoLog(fullscreenShader, "Shader Program");
+	return true;
 }
 
 extern bool LoadShaderExtensions() {
@@ -449,8 +481,7 @@ extern bool LoadShaderExtensions() {
 	glDrawBuffers = (PFNGLDRAWBUFFERSPROC)(uintptr_t)SDL_GL_GetProcAddress("glDrawBuffers");
 	glCheckFramebufferStatus = (PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glCheckFramebufferStatus");
 	if (glCreateShader && glGenFramebuffers && glGetUniformLocation && glActiveTextureProc) {
-		LoadShaders();
-		return true;
+		return LoadShaders();
 	} else {
 		return false;
 	}