Merge pull request #169 from olliwang/cancel

Added nvgCancelFrame()

src/nanovg.c

@@ -300,6 +300,11 @@ void nvgBeginFrame(NVGcontext* ctx, int windowWidth, int windowHeight, float dev
 	ctx->textTriCount = 0;
 }
 
+void nvgCancelFrame(NVGcontext* ctx)
+{
+	ctx->params.renderCancel(ctx->params.userPtr);
+}
+
 void nvgEndFrame(NVGcontext* ctx)
 {
 	ctx->params.renderFlush(ctx->params.userPtr);

src/nanovg.h

@@ -117,6 +117,9 @@ enum NVGimageFlags {
 // devicePixelRatio to: frameBufferWidth / windowWidth.
 void nvgBeginFrame(NVGcontext* ctx, int windowWidth, int windowHeight, float devicePixelRatio);
 
+// Cancels drawing the current frame.
+void nvgCancelFrame(NVGcontext* ctx);
+
 // Ends drawing flushing remaining render state.
 void nvgEndFrame(NVGcontext* ctx);
 
@@ -586,6 +589,7 @@ struct NVGparams {
 	int (*renderUpdateTexture)(void* uptr, int image, int x, int y, int w, int h, const unsigned char* data);
 	int (*renderGetTextureSize)(void* uptr, int image, int* w, int* h);
 	void (*renderViewport)(void* uptr, int width, int height);
+	void (*renderCancel)(void* uptr);
 	void (*renderFlush)(void* uptr);
 	void (*renderFill)(void* uptr, NVGpaint* paint, NVGscissor* scissor, float fringe, const float* bounds, const NVGpath* paths, int npaths);
 	void (*renderStroke)(void* uptr, NVGpaint* paint, NVGscissor* scissor, float fringe, float strokeWidth, const NVGpath* paths, int npaths);

src/nanovg_gl.h

@@ -1006,6 +1006,14 @@ static void glnvg__triangles(GLNVGcontext* gl, GLNVGcall* call)
 	glDrawArrays(GL_TRIANGLES, call->triangleOffset, call->triangleCount);
 }
 
+static void glnvg__renderCancel(void* uptr) {
+	GLNVGcontext* gl = (GLNVGcontext*)uptr;
+	gl->nverts = 0;
+	gl->npaths = 0;
+	gl->ncalls = 0;
+	gl->nuniforms = 0;
+}
+
 static void glnvg__renderFlush(void* uptr)
 {
 	GLNVGcontext* gl = (GLNVGcontext*)uptr;
@@ -1398,6 +1406,7 @@ NVGcontext* nvgCreateGLES3(int flags)
 	params.renderUpdateTexture = glnvg__renderUpdateTexture;
 	params.renderGetTextureSize = glnvg__renderGetTextureSize;
 	params.renderViewport = glnvg__renderViewport;
+	params.renderCancel = glnvg__renderCancel;
 	params.renderFlush = glnvg__renderFlush;
 	params.renderFill = glnvg__renderFill;
 	params.renderStroke = glnvg__renderStroke;