add external APIs to GL backend to get native Texture Id.

example/example_gl2.c

@@ -24,6 +24,7 @@
 #include "nanovg.h"
 #define NANOVG_GL2_IMPLEMENTATION
 #include "nanovg_gl.h"
+#include "nanovg_gl_utils.h"
 #include "demo.h"
 #include "perf.h"
 
@@ -56,8 +57,10 @@ 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.");
@@ -74,7 +77,7 @@ int main()
 	glfwWindowHint(GLFW_SAMPLES, 4);
 #endif
 
-    window = glfwCreateWindow(1000, 600, "NanoVG", NULL, NULL);
+	window = glfwCreateWindow(1000, 600, "NanoVG", NULL, NULL);
 //	window = glfwCreateWindow(1000, 600, "NanoVG", glfwGetPrimaryMonitor(), NULL);
 	if (!window) {
 		glfwTerminate();
@@ -109,6 +112,8 @@ int main()
 	glfwSetTime(0);
 	prevt = glfwGetTime();
 
+	hasFBO = nvgluCreateFramebuffer(vg, &fb, 600, 600);
+
 	while (!glfwWindowShouldClose(window))
 	{
 		double mx, my, t, dt;
@@ -116,6 +121,20 @@ 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;
@@ -141,6 +160,15 @@ 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) {
@@ -154,6 +182,7 @@ int main()
 
 	freeDemoData(vg, &data);
 
+	nvgluDeleteFramebuffer(vg, &fb);
 	nvgDeleteGL2(vg);
 
 	glfwTerminate();

src/nanovg.c

@@ -242,6 +242,11 @@ error:
 	return 0;
 }
 
+struct NVGparams* nvgInternalParams(struct NVGcontext* ctx)
+{
+    return &ctx->params;
+}
+
 void nvgDeleteInternal(struct NVGcontext* ctx)
 {
 	if (ctx == NULL) return;

src/nanovg.h

@@ -580,6 +580,8 @@ struct NVGparams {
 struct NVGcontext* nvgCreateInternal(struct NVGparams* params);
 void nvgDeleteInternal(struct NVGcontext* ctx);
 
+struct NVGparams* nvgInternalParams(struct NVGcontext* ctx);
+
 // Debug function to dump cached path data.
 void nvgDebugDumpPathCache(struct NVGcontext* ctx);
 

src/nanovg_gl.h

@@ -15,8 +15,8 @@
 //    misrepresented as being the original software.
 // 3. This notice may not be removed or altered from any source distribution.
 //
-#ifndef NANOVG_GL3_H
-#define NANOVG_GL3_H
+#ifndef NANOVG_GL_H
+#define NANOVG_GL_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -38,7 +38,7 @@ extern "C" {
 #  define NANOVG_GLES3 1
 #  define NANOVG_GL_IMPLEMENTATION 1
 #endif
-	
+
 
 #if defined NANOVG_GL2
 
@@ -62,11 +62,21 @@ void nvgDeleteGLES3(struct NVGcontext* ctx);
 
 #endif
 
+enum NVGLtextureflags {
+	NVGL_TEXTURE_FLIP_Y   = 0x01,
+	NVGL_TEXTURE_NODELETE = 0x02,
+};
+
+int nvglCreateImageFromHandle(struct NVGcontext* ctx, GLuint textureId, int flags);
+GLuint nvglImageHandle(struct NVGcontext* ctx, int image);
+void nvglImageFlags(struct NVGcontext* ctx, int image, int flags);
+
+
 #ifdef __cplusplus
 }
 #endif
 
-#endif
+#endif /* NANOVG_GL_H */
 
 #ifdef NANOVG_GL_IMPLEMENTATION
 
@@ -123,6 +133,7 @@ struct GLNVGtexture {
 	GLuint tex;
 	int width, height;
 	int type;
+	int flags;
 };
 
 enum GLNVGcallType {
@@ -242,7 +253,7 @@ static int glnvg__deleteTexture(struct GLNVGcontext* gl, int id)
 	int i;
 	for (i = 0; i < gl->ntextures; i++) {
 		if (gl->textures[i].id == id) {
-			if (gl->textures[i].tex != 0)
+			if (gl->textures[i].tex != 0 && (gl->textures[i].flags & NVGL_TEXTURE_NODELETE) == 0)
 				glDeleteTextures(1, &gl->textures[i].tex);
 			memset(&gl->textures[i], 0, sizeof(gl->textures[i]));
 			return 1;
@@ -703,9 +714,6 @@ static int glnvg__convertPaint(struct GLNVGcontext* gl, struct GLNVGfragUniforms
 	frag->innerCol = paint->innerColor;
 	frag->outerCol = paint->outerColor;
 
-	nvgTransformInverse(invxform, paint->xform);
-	glnvg__xformToMat3x4(frag->paintMat, invxform);
-
 	if (scissor->extent[0] < 0.5f || scissor->extent[1] < 0.5f) {
 		memset(frag->scissorMat, 0, sizeof(frag->scissorMat));
 		frag->scissorExt[0] = 1.0f;
@@ -720,19 +728,32 @@ static int glnvg__convertPaint(struct GLNVGcontext* gl, struct GLNVGfragUniforms
 		frag->scissorScale[0] = sqrtf(scissor->xform[0]*scissor->xform[0] + scissor->xform[2]*scissor->xform[2]) / fringe;
 		frag->scissorScale[1] = sqrtf(scissor->xform[1]*scissor->xform[1] + scissor->xform[3]*scissor->xform[3]) / fringe;
 	}
+
 	memcpy(frag->extent, paint->extent, sizeof(frag->extent));
 	frag->strokeMult = (width*0.5f + fringe*0.5f) / fringe;
 
 	if (paint->image != 0) {
 		tex = glnvg__findTexture(gl, paint->image);
 		if (tex == NULL) return 0;
+		if ((tex->flags & NVGL_TEXTURE_FLIP_Y) != 0) {
+			float flipped[6];
+			nvgTransformScale(flipped, 1.0f, -1.0f);
+			nvgTransformMultiply(flipped, paint->xform);
+			nvgTransformInverse(invxform, flipped);
+		} else {
+			nvgTransformInverse(invxform, paint->xform);
+		}
 		frag->type = NSVG_SHADER_FILLIMG;
 		frag->texType = tex->type == NVG_TEXTURE_RGBA ? 0 : 1;
 	} else {
 		frag->type = NSVG_SHADER_FILLGRAD;
 		frag->radius = paint->radius;
 		frag->feather = paint->feather;
+		nvgTransformInverse(invxform, paint->xform);
 	}
+
+	glnvg__xformToMat3x4(frag->paintMat, invxform);
+
 	return 1;
 }
 
@@ -1222,7 +1243,7 @@ static void glnvg__renderDelete(void* uptr)
 		glDeleteBuffers(1, &gl->vertBuf);
 
 	for (i = 0; i < gl->ntextures; i++) {
-		if (gl->textures[i].tex != 0)
+		if (gl->textures[i].tex != 0 && (gl->textures[i].flags & NVGL_TEXTURE_NODELETE) == 0)
 			glDeleteTextures(1, &gl->textures[i].tex);
 	}
 	free(gl->textures);
@@ -1290,4 +1311,36 @@ void nvgDeleteGLES3(struct NVGcontext* ctx)
 	nvgDeleteInternal(ctx);
 }
 
-#endif
+int nvglCreateImageFromHandle(struct NVGcontext* ctx, GLuint textureId, int flags)
+{
+	struct GLNVGcontext* gl = (struct GLNVGcontext*)nvgInternalParams(ctx)->userPtr;
+	struct GLNVGtexture* tex = glnvg__allocTexture(gl);
+
+	if (tex == NULL) return 0;
+
+	tex->tex = textureId;
+	tex->type = NVG_TEXTURE_RGBA;
+    tex->flags = 0;
+	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);
+	glBindTexture(GL_TEXTURE_2D, 0);
+
+	return tex->id;
+}
+
+GLuint nvglImageHandle(struct NVGcontext* ctx, int image)
+{
+	struct GLNVGcontext* gl = (struct GLNVGcontext*)nvgInternalParams(ctx)->userPtr;
+	struct GLNVGtexture* tex = glnvg__findTexture(gl, image);
+	return tex->tex;
+}
+
+void nvglImageFlags(struct NVGcontext* ctx, int image, int flags)
+{
+	struct GLNVGcontext* gl = (struct GLNVGcontext*)nvgInternalParams(ctx)->userPtr;
+	struct GLNVGtexture* tex = glnvg__findTexture(gl, image);
+	tex->flags = flags;
+}
+
+#endif /* NANOVG_GL_IMPLEMENTATION */

src/nanovg_gl_utils.h

@@ -0,0 +1,61 @@
+#ifndef gl_utils_h
+#define gl_utils_h
+
+
+struct NVGLUframebuffer {
+    struct NVGcontext* ctx;
+    GLuint fbo;
+    GLuint rbo;
+    GLuint texture;
+    int image;
+};
+
+int nvgluCreateFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb, int w, int h);
+void nvgluDeleteFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb);
+
+
+#endif /* gl_utils_h */
+
+#ifdef NANOVG_GL_IMPLEMENTATION
+
+int nvgluCreateFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb, int w, int h) {
+	fb->image = nvgCreateImageRGBA(ctx, w, h, NULL);
+	fb->texture = nvglImageHandle(ctx, fb->image);
+	nvglImageFlags(ctx, fb->image, NVGL_TEXTURE_FLIP_Y);
+
+	/* 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_DEPTH24_STENCIL8, 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) {
+		nvgluDeleteFramebuffer(ctx, fb);
+		return 0;
+	}
+	return 1;
+}
+
+void nvgluDeleteFramebuffer(struct NVGcontext* ctx, struct NVGLUframebuffer* fb) {
+	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;
+}
+
+
+#endif /* NANOVG_GL_IMPLEMENTATION */
+/* vim: set ft=c nu noet ts=4 sw=4 : */