Start updating nanovg

dgl/src/nanovg/nanovg_gl_utils.h

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+//
+// 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 {
+	NVGcontext* ctx;
+	GLuint fbo;
+	GLuint rbo;
+	GLuint texture;
+	int image;
+};
+typedef struct NVGLUframebuffer NVGLUframebuffer;
+
+// Helper function to create GL frame buffer to render to.
+void nvgluBindFramebuffer(NVGLUframebuffer* fb);
+NVGLUframebuffer* nvgluCreateFramebuffer(NVGcontext* ctx, int w, int h, int imageFlags);
+void nvgluDeleteFramebuffer(NVGcontext* ctx, NVGLUframebuffer* fb);
+
+#endif // NANOVG_GL_UTILS_H
+
+#ifdef NANOVG_GL_IMPLEMENTATION
+
+#if defined(NANOVG_GL3) || defined(NANOVG_GLES2) || defined(NANOVG_GLES3)
+// FBO is core in OpenGL 3>.
+#	define NANOVG_FBO_VALID 1
+#elif defined(NANOVG_GL2)
+// On OS X including glext defines FBO on GL2 too.
+#	ifdef __APPLE__
+#		include <OpenGL/glext.h>
+#		define NANOVG_FBO_VALID 1
+#	endif
+#endif
+
+static GLint defaultFBO = -1;
+
+NVGLUframebuffer* nvgluCreateFramebuffer(NVGcontext* ctx, int w, int h, int imageFlags)
+{
+#ifdef NANOVG_FBO_VALID
+	GLint defaultFBO;
+	GLint defaultRBO;
+	NVGLUframebuffer* fb = NULL;
+
+	glGetIntegerv(GL_FRAMEBUFFER_BINDING, &defaultFBO);
+	glGetIntegerv(GL_RENDERBUFFER_BINDING, &defaultRBO);
+
+	fb = (NVGLUframebuffer*)malloc(sizeof(NVGLUframebuffer));
+	if (fb == NULL) goto error;
+	memset(fb, 0, sizeof(NVGLUframebuffer));
+
+	fb->image = nvgCreateImageRGBA(ctx, w, h, imageFlags | NVG_IMAGE_FLIPY | NVG_IMAGE_PREMULTIPLIED, NULL);
+	fb->texture = nvglImageHandle(ctx, fb->image);
+
+	// frame buffer object
+	glGenFramebuffers(1, &fb->fbo);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb->fbo);
+
+	// render buffer object
+	glGenRenderbuffers(1, &fb->rbo);
+	glBindRenderbuffer(GL_RENDERBUFFER, fb->rbo);
+	glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, w, h);
+
+	// 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) goto error;
+
+	glBindFramebuffer(GL_FRAMEBUFFER, defaultFBO);
+	glBindRenderbuffer(GL_RENDERBUFFER, defaultRBO);
+	return fb;
+error:
+	glBindFramebuffer(GL_FRAMEBUFFER, defaultFBO);
+	glBindRenderbuffer(GL_RENDERBUFFER, defaultRBO);
+	nvgluDeleteFramebuffer(ctx, fb);
+	return NULL;
+#else
+	NVG_NOTUSED(ctx);
+	NVG_NOTUSED(w);
+	NVG_NOTUSED(h);
+	NVG_NOTUSED(imageFlags);
+	return NULL;
+#endif
+}
+
+void nvgluBindFramebuffer(NVGLUframebuffer* fb)
+{
+#ifdef NANOVG_FBO_VALID
+	if (defaultFBO == -1) glGetIntegerv(GL_FRAMEBUFFER_BINDING, &defaultFBO);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb != NULL ? fb->fbo : defaultFBO);
+#else
+	NVG_NOTUSED(fb);
+#endif
+}
+
+void nvgluDeleteFramebuffer(NVGcontext* ctx, NVGLUframebuffer* fb)
+{
+#ifdef NANOVG_FBO_VALID
+	if (fb == NULL) return;
+	if (fb->fbo != 0)
+		glDeleteFramebuffers(1, &fb->fbo);
+	if (fb->rbo != 0)
+		glDeleteRenderbuffers(1, &fb->rbo);
+	if (fb->image >= 0)
+		nvgDeleteImage(ctx, fb->image);
+	fb->fbo = 0;
+	fb->rbo = 0;
+	fb->texture = 0;
+	fb->image = -1;
+	free(fb);
+#else
+	NVG_NOTUSED(ctx);
+	NVG_NOTUSED(fb);
+#endif
+}
+
+#endif // NANOVG_GL_IMPLEMENTATION