Fixes and tweaks for frame buffer handling

- fixed flags setup in nvglCreateImageFromHandle
- changed frame buffer to only compile on GL3
- changed nvgluCreateFramebuffer() to return FBO struct instead of
filling existing one (for consistency)

example/example_gl2.c

@@ -57,10 +57,8 @@ int main()
 	GLFWwindow* window;
 	struct DemoData data;
 	struct NVGcontext* vg = NULL;
-	struct NVGLUframebuffer fb;
 	struct PerfGraph fps;
 	double prevt = 0;
-	int hasFBO;
 
 	if (!glfwInit()) {
 		printf("Failed to init GLFW.");
@@ -112,8 +110,6 @@ int main()
 	glfwSetTime(0);
 	prevt = glfwGetTime();
 
-	hasFBO = nvgluCreateFramebuffer(vg, &fb, 600, 600);
-
 	while (!glfwWindowShouldClose(window))
 	{
 		double mx, my, t, dt;
@@ -121,20 +117,6 @@ int main()
 		int fbWidth, fbHeight;
 		float pxRatio;
 
-		if (hasFBO) {
-			int fboWidth, fboHeight;
-			nvgImageSize(vg, fb.image, &fboWidth, &fboHeight);
-			// Draw some stull to an FBO as a test
-			glBindFramebuffer(GL_FRAMEBUFFER, fb.fbo);
-			glViewport(0, 0, fboWidth, fboHeight);
-			glClearColor(0, 0, 0, 0);
-			glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
-			nvgBeginFrame(vg, fboWidth, fboHeight, pxRatio, NVG_PREMULTIPLIED_ALPHA);
-			renderDemo(vg, mx, my, fboWidth, fboHeight, t, blowup, &data);
-			nvgEndFrame(vg);
-			glBindFramebuffer(GL_FRAMEBUFFER, 0);
-		}
-
 		t = glfwGetTime();
 		dt = t - prevt;
 		prevt = t;
@@ -160,15 +142,6 @@ int main()
 		renderDemo(vg, mx,my, winWidth,winHeight, t, blowup, &data);
 		renderGraph(vg, 5,5, &fps);
 
-		if (hasFBO) {
-			struct NVGpaint img = nvgImagePattern(vg, 0, 0, 150, 150, 0, fb.image, 0);
-			nvgBeginPath(vg);
-			nvgTranslate(vg, 540, 300);
-			nvgRect(vg, 0, 0, 150, 150);
-			nvgFillPaint(vg, img);
-			nvgFill(vg);
-		}
-
 		nvgEndFrame(vg);
 
 		if (screenshot) {
@@ -182,7 +155,6 @@ int main()
 
 	freeDemoData(vg, &data);
 
-	nvgluDeleteFramebuffer(vg, &fb);
 	nvgDeleteGL2(vg);
 
 	glfwTerminate();

example/example_gl3.c

@@ -27,6 +27,7 @@
 #include "nanovg.h"
 #define NANOVG_GL3_IMPLEMENTATION
 #include "nanovg_gl.h"
+#include "nanovg_gl_utils.h"
 #include "demo.h"
 #include "perf.h"
 
@@ -61,6 +62,7 @@ int main()
 	struct GPUtimer gpuTimer;
 	struct PerfGraph fps, cpuGraph, gpuGraph;
 	double prevt = 0, cpuTime = 0;
+	struct NVGLUframebuffer* fb = NULL;
 
 	if (!glfwInit()) {
 		printf("Failed to init GLFW.");
@@ -122,6 +124,8 @@ int main()
 	glfwSetTime(0);
 	prevt = glfwGetTime();
 
+	fb = nvgluCreateFramebuffer(vg, 600, 600);
+
 	while (!glfwWindowShouldClose(window))
 	{
 		double mx, my, t, dt;
@@ -143,6 +147,20 @@ int main()
 		// Calculate pixel ration for hi-dpi devices.
 		pxRatio = (float)fbWidth / (float)winWidth;
 
+		if (fb != NULL) {
+			int fboWidth, fboHeight;
+			nvgImageSize(vg, fb->image, &fboWidth, &fboHeight);
+			// Draw some stull to an FBO as a test
+			nvgluBindFramebuffer(fb);
+			glViewport(0, 0, fboWidth, fboHeight);
+			glClearColor(0, 0, 0, 0);
+			glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
+			nvgBeginFrame(vg, fboWidth, fboHeight, pxRatio, NVG_PREMULTIPLIED_ALPHA);
+			renderDemo(vg, mx, my, fboWidth, fboHeight, t, blowup, &data);
+			nvgEndFrame(vg);
+			nvgluBindFramebuffer(NULL);
+		}
+
 		// Update and render
 		glViewport(0, 0, fbWidth, fbHeight);
 		if (premult)
@@ -160,6 +178,15 @@ int main()
 		if (gpuTimer.supported)
 			renderGraph(vg, 5+200+5+200+5,5, &gpuGraph);
 
+		if (fb != NULL) {
+			struct NVGpaint img = nvgImagePattern(vg, 0, 0, 150, 150, 0, fb->image, 0);
+			nvgBeginPath(vg);
+			nvgTranslate(vg, 540, 300);
+			nvgRect(vg, 0, 0, 150, 150);
+			nvgFillPaint(vg, img);
+			nvgFill(vg);
+		}
+
 		nvgEndFrame(vg);
 
 		// Measure the CPU time taken excluding swap buffers (as the swap may wait for GPU)
@@ -184,6 +211,8 @@ int main()
 
 	freeDemoData(vg, &data);
 
+	nvgluDeleteFramebuffer(vg, fb);
+
 	nvgDeleteGL3(vg);
 
 	printf("Average Frame Time: %.2f ms\n", getGraphAverage(&fps) * 1000.0f);

example/example_gles2.c

@@ -22,6 +22,7 @@
 #include "nanovg.h"
 #define NANOVG_GLES2_IMPLEMENTATION
 #include "nanovg_gl.h"
+#include "nanovg_gl_utils.h"
 #include "demo.h"
 #include "perf.h"
 

example/example_gles3.c

@@ -22,6 +22,7 @@
 #include "nanovg.h"
 #define NANOVG_GLES3_IMPLEMENTATION
 #include "nanovg_gl.h"
+#include "nanovg_gl_utils.h"
 #include "demo.h"
 #include "perf.h"
 

src/nanovg_gl.h

@@ -1324,7 +1324,7 @@ int nvglCreateImageFromHandle(struct NVGcontext* ctx, GLuint textureId, int flag
 
 	tex->tex = textureId;
 	tex->type = NVG_TEXTURE_RGBA;
-    tex->flags = 0;
+    tex->flags = flags;
 	glBindTexture(GL_TEXTURE_2D, tex->tex);
 	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &tex->width);
 	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &tex->height);

src/nanovg_gl_utils.h

@@ -1,49 +1,91 @@
-#ifndef gl_utils_h
-#define gl_utils_h
-
+//
+// Copyright (c) 2009-2013 Mikko Mononen memon@inside.org
+//
+// This software is provided 'as-is', without any express or implied
+// warranty.  In no event will the authors be held liable for any damages
+// arising from the use of this software.
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+// 1. The origin of this software must not be misrepresented; you must not
+//    claim that you wrote the original software. If you use this software
+//    in a product, an acknowledgment in the product documentation would be
+//    appreciated but is not required.
+// 2. Altered source versions must be plainly marked as such, and must not be
+//    misrepresented as being the original software.
+// 3. This notice may not be removed or altered from any source distribution.
+//
+#ifndef NANOVG_GL_UTILS_H
+#define NANOVG_GL_UTILS_H
 
 struct NVGLUframebuffer {
-    struct NVGcontext* ctx;
-    GLuint fbo;
-    GLuint rbo;
-    GLuint texture;
-    int image;
+	struct NVGcontext* ctx;
+	GLuint fbo;
+	GLuint rbo;
+	GLuint texture;
+	int image;
 };
 
-int nvgluCreateFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb, int w, int h);
+// Helper function to create GL frame buffer to render to.
+struct NVGLUframebuffer* nvgluCreateFramebuffer(struct NVGcontext* ctx, int w, int h);
 void nvgluDeleteFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb);
 
-
-#endif /* gl_utils_h */
+#endif // NANOVG_GL_UTILS_H
 
 #ifdef NANOVG_GL_IMPLEMENTATION
 
-int nvgluCreateFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb, int w, int h) {
+struct NVGLUframebuffer* nvgluCreateFramebuffer(struct NVGcontext* ctx, int w, int h)
+{
+#ifdef NANOVG_GL3
+	struct NVGLUframebuffer* fb = NULL;
+	fb = (struct NVGLUframebuffer*)malloc(sizeof(struct NVGLUframebuffer));
+	if (fb == NULL) goto error;
+	memset(fb, 0, sizeof(struct NVGLUframebuffer));
+
 	fb->image = nvgCreateImageRGBA(ctx, w, h, NULL);
 	fb->texture = nvglImageHandle(ctx, fb->image);
 	nvglImageFlags(ctx, fb->image, NVGL_TEXTURE_FLIP_Y);
 
-	/* frame buffer object */
+	// frame buffer object
 	glGenFramebuffers(1, &fb->fbo);
 	glBindFramebuffer(GL_FRAMEBUFFER, fb->fbo);
 
-	/* render buffer object */
+	// render buffer object
 	glGenRenderbuffers(1, &fb->rbo);
 	glBindRenderbuffer(GL_RENDERBUFFER, fb->rbo);
 	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, w, h);
 
-	/* combine all */
+	// combine all
 	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, fb->texture, 0);
 	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, fb->rbo);
 
-	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
-		nvgluDeleteFramebuffer(ctx, fb);
-		return 0;
-	}
-	return 1;
+	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) goto error;
+
+	return fb;
+error:
+	nvgluDeleteFramebuffer(ctx, fb);
+	return NULL;
+#else
+	NVG_NOTUSED(ctx);
+	NVG_NOTUSED(w);
+	NVG_NOTUSED(h);
+	return NULL;
+#endif
 }
 
-void nvgluDeleteFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb) {
+void nvgluBindFramebuffer(struct NVGLUframebuffer* fb)
+{
+#ifdef NANOVG_GL3
+	glBindFramebuffer(GL_FRAMEBUFFER, fb != NULL ? fb->fbo : 0);
+#else
+	NVG_NOTUSED(fb);
+#endif
+}
+
+void nvgluDeleteFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb)
+{
+#ifdef NANOVG_GL3
+	if (fb == NULL) return;
 	if (fb->fbo != 0)
 		glDeleteFramebuffers(1, &fb->fbo);
 	if (fb->rbo != 0)
@@ -54,8 +96,11 @@ void nvgluDeleteFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb)
 	fb->rbo = 0;
 	fb->texture = 0;
 	fb->image = -1;
+	free(fb);
+#else
+	NVG_NOTUSED(ctx);
+	NVG_NOTUSED(fb);
+#endif
 }
 
-
-#endif /* NANOVG_GL_IMPLEMENTATION */
-/* vim: set ft=c nu noet ts=4 sw=4 : */
+#endif // NANOVG_GL_IMPLEMENTATION