Clay Engine: Replace Manual depth test by depth copy.

This avoid glitches due to float comparison precision.

2 files changed, 38 insertions, 0 deletions

diff --git a/source/blender/gpu/GPU_framebuffer.h b/source/blender/gpu/GPU_framebuffer.h
index 9611a6f0577..15617832c9b 100644
--- a/source/blender/gpu/GPU_framebuffer.h
+++ b/source/blender/gpu/GPU_framebuffer.h
@@ -67,6 +67,10 @@ void GPU_framebuffer_blur(
         GPUFrameBuffer *fb, struct GPUTexture *tex,
         GPUFrameBuffer *blurfb, struct GPUTexture *blurtex);
 
+void GPU_framebuffer_blit(
+        GPUFrameBuffer *fb_read, int read_slot,
+        GPUFrameBuffer *fb_write, int write_slot, bool use_depth);
+
 /* GPU OffScreen
  * - wrapper around framebuffer and texture for simple offscreen drawing
  * - changes size if graphics card can't support it */
diff --git a/source/blender/gpu/intern/gpu_framebuffer.c b/source/blender/gpu/intern/gpu_framebuffer.c
index 1efc451f4a8..3b44abb479c 100644
--- a/source/blender/gpu/intern/gpu_framebuffer.c
+++ b/source/blender/gpu/intern/gpu_framebuffer.c
@@ -448,6 +448,40 @@ void GPU_framebuffer_blur(
 	GPU_shader_unbind();
 }
 
+void GPU_framebuffer_blit(GPUFrameBuffer *fb_read, int read_slot, GPUFrameBuffer *fb_write, int write_slot, bool use_depth)
+{
+	GPUTexture *read_tex = (use_depth) ? fb_read->depthtex : fb_read->colortex[read_slot];
+	GPUTexture *write_tex = (use_depth) ? fb_write->depthtex : fb_write->colortex[write_slot];
+	int read_attach = (use_depth) ? GL_DEPTH_ATTACHMENT : GL_COLOR_ATTACHMENT0 + GPU_texture_framebuffer_attachment(read_tex);
+	int write_attach = (use_depth) ? GL_DEPTH_ATTACHMENT : GL_COLOR_ATTACHMENT0 + GPU_texture_framebuffer_attachment(write_tex);
+	int read_bind = GPU_texture_opengl_bindcode(read_tex);
+	int write_bind = GPU_texture_opengl_bindcode(write_tex);
+	const int read_w = GPU_texture_width(read_tex);
+	const int read_h = GPU_texture_height(read_tex);
+	const int write_w = GPU_texture_width(write_tex);
+	const int write_h = GPU_texture_height(write_tex);
+
+	/* read from multi-sample buffer */
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, fb_read->object);
+	glFramebufferTexture2D(
+	        GL_READ_FRAMEBUFFER, read_attach,
+	        GL_TEXTURE_2D, read_bind, 0);
+	BLI_assert(glCheckFramebufferStatusEXT(GL_READ_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
+
+	/* write into new single-sample buffer */
+	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fb_write->object);
+	glFramebufferTexture2D(
+	        GL_DRAW_FRAMEBUFFER, write_attach,
+	        GL_TEXTURE_2D, write_bind, 0);
+	BLI_assert(glCheckFramebufferStatusEXT(GL_DRAW_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
+
+	glBlitFramebuffer(0, 0, read_w, read_h, 0, 0, write_w, write_h, (use_depth) ? GL_DEPTH_BUFFER_BIT : GL_COLOR_BUFFER_BIT, GL_NEAREST);
+
+	/* Restore previous framebuffer */
+	glBindFramebuffer(GL_FRAMEBUFFER, GG.currentfb);
+	glDrawBuffer(GL_COLOR_ATTACHMENT0);
+}
+
 /* GPUOffScreen */
 
 struct GPUOffScreen {