Squashed 'external/parallel-rdp/parallel-rdp-standalone/' content from commit d1cc912c5c4

git-subtree-dir: external/parallel-rdp/parallel-rdp-standalone
git-subtree-split: d1cc912c5c47abaf9b6b155d3cd15255df65cf5b

parallel-rdp/shaders/coverage.h

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+/* Copyright (c) 2020 Themaister
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef COVERAGE_H_
+#define COVERAGE_H_
+
+#include "data_structures.h"
+
+const int SUBPIXELS_LOG2 = 2;
+const int SUBPIXELS = 1 << SUBPIXELS_LOG2;
+
+u8 compute_coverage(u16x4 xleft, u16x4 xright, int x)
+{
+	u16x4 xshift = u16x4(0, 4, 2, 6) + (u16(x) << U16_C(3));
+	bvec4 clip_lo_x01 = lessThan(xshift, xleft.xxyy);
+	bvec4 clip_lo_x23 = lessThan(xshift, xleft.zzww);
+	bvec4 clip_hi_x01 = greaterThanEqual(xshift, xright.xxyy);
+	bvec4 clip_hi_x23 = greaterThanEqual(xshift, xright.zzww);
+
+	u8x4 clip_x0 = u8x4(clip_lo_x01) | u8x4(clip_hi_x01);
+	u8x4 clip_x1 = u8x4(clip_lo_x23) | u8x4(clip_hi_x23);
+	u8x4 clip_x = clip_x0 * u8x4(1, 2, 4, 8) + clip_x1 * u8x4(16, 32, 64, 128);
+	u8 clip_coverage = (clip_x.x | clip_x.y) | (clip_x.z | clip_x.w);
+	return ~clip_coverage & U8_C(0xff);
+}
+
+const int COVERAGE_CLAMP = 0;
+const int COVERAGE_WRAP = 1;
+const int COVERAGE_ZAP = 2;
+const int COVERAGE_SAVE = 3;
+
+int blend_coverage(int coverage, int memory_coverage, bool blend_en, int mode)
+{
+	int res = 0;
+	switch (mode)
+	{
+	case COVERAGE_CLAMP:
+	{
+		if (blend_en)
+			res = min(7, memory_coverage + coverage); // image_read_en to read memory coverage, otherwise, it's 7.
+		else
+			res = (coverage - 1) & 7;
+		break;
+	}
+
+	case COVERAGE_WRAP:
+		res = (coverage + memory_coverage) & 7;
+		break;
+
+	case COVERAGE_ZAP:
+		res = 7;
+		break;
+
+	case COVERAGE_SAVE:
+		res = memory_coverage;
+		break;
+	}
+
+	return res;
+}
+
+#endif