Differential D6714 Diff 21365 source/blender/draw/engines/basic/shaders/conservative_depth_geom.glsl

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source/blender/draw/engines/basic/shaders/conservative_depth_geom.glsl

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				/* Adaptation of Conservative Rasterization
				* from GPU Gems 2
				* Using method 2.
				* https://developer.nvidia.com/gpugems/gpugems2/part-v-image-oriented-computing/chapter-42-conservative-rasterization
				*/

				layout(triangles) in;
				layout(triangle_strip, max_vertices = 3) out;

				RESOURCE_ID_VARYING

				uniform vec2 sizeViewport;
				uniform vec2 sizeViewportInv;

				flat out vec4 bbox;

				#define FLT_MAX 9999999999999.0
				campbellbartonUnsubmitted Not Done Inline Actions Suggest calling this `BOUNDS_MAX` or similar, otherwise set to `3.40282347E+38F`. campbellbarton: Suggest calling this `BOUNDS_MAX` or similar, otherwise set to `3.40282347E+38F`.

				/**
				* Adds a new point to the bounding box. This method can be simplified if orthogonal
				* projection is assumed
				*/
				void bbox_min_max(vec4 pos, inout vec4 bbox)
				{
				if (pos.w < 0) {
				bbox.xy = min(bbox.xy, pos.xy);
				bbox.zw = max(bbox.zw, pos.xy);
				}
				else {
				bbox.xy = min(bbox.xy, pos.xy / pos.w);
				bbox.zw = max(bbox.zw, pos.xy / pos.w);
				}
				}

				void main()
				{
				vec4 curr_pos, prev_pos, next_pos;
				campbellbartonUnsubmitted Not Done Inline Actions Unused variables. campbellbarton: Unused variables.

				/* Compute the screen space bounding box of the triangle. */
				bbox = vec4(FLT_MAX, FLT_MAX, -FLT_MAX, -FLT_MAX);
				bbox_min_max(gl_in[0].gl_Position, bbox);
				bbox_min_max(gl_in[1].gl_Position, bbox);
				bbox_min_max(gl_in[2].gl_Position, bbox);
				/* Convert to pixel space and enlarge the BBox. */
				bbox = (bbox * 0.5 + 0.5) * sizeViewport.xyxy;
				/* Detect failure cases where triangles would produce no fragments. */
				bvec2 is_subpixel = lessThan(bbox.zw - bbox.xy, vec2(1.0));
				/* Compute plane normal in ndc space. */
				vec3 pos0 = gl_in[0].gl_Position.xyz / gl_in[0].gl_Position.w;
				vec3 pos1 = gl_in[1].gl_Position.xyz / gl_in[1].gl_Position.w;
				vec3 pos2 = gl_in[2].gl_Position.xyz / gl_in[2].gl_Position.w;
				vec3 plane = normalize(cross(pos1 - pos0, pos2 - pos0));
				/* View aligned triangle. */
				bool is_coplanar = abs(plane.z) < 0.00001;
				campbellbartonUnsubmitted Not Done Inline Actions Could use define for the constant. campbellbarton: Could use define for the constant.

				for (int i = 0; i < 3; i++) {
				gl_Position = gl_in[i].gl_Position;
				if (all(is_subpixel)) {
				vec2 ofs = (i == 0) ? vec2(-1.0) : ((i == 1) ? vec2(2.0, -1.0) : vec2(-1.0, 2.0));
				/* HACK: Fix cases where the triangle is too small make it cover at least one pixel. */
				gl_Position.xy += sizeViewportInv.xy * gl_Position.w * ofs;
				}
				/* Test if the triangle is almost parralele with the view to avoid precision issues. */
				else if (any(is_subpixel) \|\| is_coplanar) {
				/* HACK: Fix cases where the triangle is Parallel to the view by deforming it slightly. */
				vec2 ofs = (i == 0) ? vec2(-1.0) : ((i == 1) ? vec2(1.0, -1.0) : vec2(1.0));
				gl_Position.xy += sizeViewportInv.xy * gl_Position.w * ofs;
				}
				else {
				/* Triangle expansion should happen here, but we decide to not implement it for
				* depth precision & performance reasons. */
				}

				#ifdef USE_WORLD_CLIP_PLANES
				world_clip_planes_set_clip_distance(gl_in[i].gl_ClipDistance);
				#endif
				EmitVertex();
				}
				EndPrimitive();
				}
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