Exemple #1
0
            public static Bc7Block EncodeBlock(RawBlock4X4Rgba32 rawBlock)
            {
                bool hasAlpha = rawBlock.HasTransparentPixels();

                var indexBlock2 = CreateClusterIndexBlock(rawBlock, out int clusters2, 2);
                var indexBlock3 = CreateClusterIndexBlock(rawBlock, out int clusters3, 3);

                if (clusters2 < 2)
                {
                    clusters2   = clusters3;
                    indexBlock2 = indexBlock3;
                }

                int[] best2SubsetPartitions = Bc7EncodingHelpers.Rank2SubsetPartitions(indexBlock2, clusters2);
                int[] best3SubsetPartitions = Bc7EncodingHelpers.Rank3SubsetPartitions(indexBlock3, clusters3);


                float    bestError = 99999;
                Bc7Block best      = new Bc7Block();
                int      tries     = 0;

                foreach (Bc7Block block in TryMethods(rawBlock, best2SubsetPartitions, best3SubsetPartitions, hasAlpha))
                {
                    var   decoded = block.Decode();
                    float error   = rawBlock.CalculateYCbCrAlphaError(decoded);
                    tries++;

                    if (error < bestError)
                    {
                        best      = block;
                        bestError = error;
                    }

                    if (error < errorThreshold || tries > maxTries)
                    {
                        break;
                    }
                }

                return(best);
            }
        public static Bc7Block EncodeBlock(RawBlock4X4Rgba32 block, int startingVariation)
        {
            var type = Bc7BlockType.Type5;

            Span <Bc7Block> outputs = stackalloc Bc7Block[4];

            for (int rotation = 0; rotation < 4; rotation++)
            {
                var      rotatedBlock = Bc7EncodingHelpers.RotateBlockColors(block, rotation);
                Bc7Block output       = new Bc7Block();

                Bc7EncodingHelpers.GetInitialUnscaledEndpoints(rotatedBlock, out var ep0, out var ep1);

                ColorRgba32 scaledEp0 =
                    Bc7EncodingHelpers.ScaleDownEndpoint(ep0, type, false, out byte _);
                ColorRgba32 scaledEp1 =
                    Bc7EncodingHelpers.ScaleDownEndpoint(ep1, type, false, out byte _);

                byte pBit = 0;                 //fake pBit

                Bc7EncodingHelpers.OptimizeSubsetEndpointsWithPBit(type, rotatedBlock, ref scaledEp0,
                                                                   ref scaledEp1, ref pBit, ref pBit, startingVariation, partitionTable, subset, false, true);

                ep0 = Bc7EncodingHelpers.ExpandEndpoint(type, scaledEp0, 0);
                ep1 = Bc7EncodingHelpers.ExpandEndpoint(type, scaledEp1, 0);
                byte[] colorIndices = new byte[16];
                byte[] alphaIndices = new byte[16];
                Bc7EncodingHelpers.FillAlphaColorIndices(type, rotatedBlock,
                                                         ep0,
                                                         ep1,
                                                         colorIndices, alphaIndices);

                bool needsRedo = false;

                if ((colorIndices[0] & 0b10) > 0)                 //If anchor index most significant bit is 1, switch endpoints
                {
                    var c      = scaledEp0;
                    var alpha0 = scaledEp0.a;
                    var alpha1 = scaledEp1.a;

                    scaledEp0   = scaledEp1;
                    scaledEp1   = c;
                    scaledEp0.a = alpha0;
                    scaledEp1.a = alpha1;

                    needsRedo = true;
                }
                if ((alphaIndices[0] & 0b10) > 0)                 //If anchor index most significant bit is 1, switch endpoints
                {
                    var a = scaledEp0.a;

                    scaledEp0.a = scaledEp1.a;
                    scaledEp1.a = a;

                    needsRedo = true;
                }

                if (needsRedo)
                {
                    //redo indices
                    ep0 = Bc7EncodingHelpers.ExpandEndpoint(type, scaledEp0, 0);
                    ep1 = Bc7EncodingHelpers.ExpandEndpoint(type, scaledEp1, 0);
                    Bc7EncodingHelpers.FillAlphaColorIndices(type, rotatedBlock,
                                                             ep0,
                                                             ep1,
                                                             colorIndices, alphaIndices);
                }


                output.PackType5(rotation, new[] {
                    new byte[] { scaledEp0.r, scaledEp0.g, scaledEp0.b },
                    new byte[] { scaledEp1.r, scaledEp1.g, scaledEp1.b },
                },
                                 new[] { scaledEp0.a, scaledEp1.a },
                                 colorIndices, alphaIndices);

                outputs[rotation] = output;
            }

            int   bestIndex = 0;
            float bestError = 0;
            bool  first     = true;

            // Find best out of generated blocks
            for (int i = 0; i < outputs.Length; i++)
            {
                var decoded = outputs[i].Decode();

                float error = block.CalculateYCbCrAlphaError(decoded);
                if (error < bestError || first)
                {
                    first     = false;
                    bestError = error;
                    bestIndex = i;
                }
            }

            return(outputs[bestIndex]);
        }
Exemple #3
0
        public static Bc7Block EncodeBlock(RawBlock4X4Rgba32 block, int startingVariation, int bestPartition)
        {
            Bc7Block           output = new Bc7Block();
            const Bc7BlockType type   = Bc7BlockType.Type2;

            ColorRgba32[]      endpoints      = new ColorRgba32[6];
            ReadOnlySpan <int> partitionTable = Bc7Block.Subsets3PartitionTable[bestPartition];

            byte[] indices = new byte[16];

            int[] anchorIndices = new int[] {
                0,
                Bc7Block.Subsets3AnchorIndices2[bestPartition],
                Bc7Block.Subsets3AnchorIndices3[bestPartition]
            };

            for (int subset = 0; subset < 3; subset++)
            {
                Bc7EncodingHelpers.GetInitialUnscaledEndpointsForSubset(block, out var ep0, out var ep1,
                                                                        partitionTable, subset);
                ColorRgba32 scaledEp0 =
                    Bc7EncodingHelpers.ScaleDownEndpoint(ep0, type, true, out byte _);
                ColorRgba32 scaledEp1 =
                    Bc7EncodingHelpers.ScaleDownEndpoint(ep1, type, true, out byte _);

                byte pBit = 0;
                Bc7EncodingHelpers.OptimizeSubsetEndpointsWithPBit(type, block, ref scaledEp0,
                                                                   ref scaledEp1, ref pBit, ref pBit, startingVariation, partitionTable, subset, false, false);

                ep0 = Bc7EncodingHelpers.ExpandEndpoint(type, scaledEp0, 0);
                ep1 = Bc7EncodingHelpers.ExpandEndpoint(type, scaledEp1, 0);
                Bc7EncodingHelpers.FillSubsetIndices(type, block,
                                                     ep0,
                                                     ep1,
                                                     partitionTable, subset, indices);

                if ((indices[anchorIndices[subset]] & 0b10) > 0)                 //If anchor index most significant bit is 1, switch endpoints
                {
                    var c = scaledEp0;

                    scaledEp0 = scaledEp1;
                    scaledEp1 = c;

                    //redo indices
                    ep0 = Bc7EncodingHelpers.ExpandEndpoint(type, scaledEp0, 0);
                    ep1 = Bc7EncodingHelpers.ExpandEndpoint(type, scaledEp1, 0);
                    Bc7EncodingHelpers.FillSubsetIndices(type, block,
                                                         ep0,
                                                         ep1,
                                                         partitionTable, subset, indices);
                }

                endpoints[subset * 2]     = scaledEp0;
                endpoints[subset * 2 + 1] = scaledEp1;
            }

            output.PackType2(bestPartition, new[] {
                new byte[] { endpoints[0].r, endpoints[0].g, endpoints[0].b },
                new byte[] { endpoints[1].r, endpoints[1].g, endpoints[1].b },
                new byte[] { endpoints[2].r, endpoints[2].g, endpoints[2].b },
                new byte[] { endpoints[3].r, endpoints[3].g, endpoints[3].b },
                new byte[] { endpoints[4].r, endpoints[4].g, endpoints[4].b },
                new byte[] { endpoints[5].r, endpoints[5].g, endpoints[5].b }
            },
                             indices);

            return(output);
        }
		public static Bc7Block EncodeBlock(RawBlock4X4Rgba32 block, int startingVariation)
		{
			bool hasAlpha = block.HasTransparentPixels();

			Bc7Block output = new Bc7Block();
			Bc7EncodingHelpers.GetInitialUnscaledEndpoints(block, out var ep0, out var ep1);

			ColorRgba32 scaledEp0 =
				Bc7EncodingHelpers.ScaleDownEndpoint(ep0, Bc7BlockType.Type6, false, out byte pBit0);
			ColorRgba32 scaledEp1 =
				Bc7EncodingHelpers.ScaleDownEndpoint(ep1, Bc7BlockType.Type6, false, out byte pBit1);

			ReadOnlySpan<int> partitionTable = new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
			const int subset = 0;

			//Force 255 alpha if fully opaque
			if (!hasAlpha)
			{
				pBit0 = 1;
				pBit1 = 1;
			}

			Bc7EncodingHelpers.OptimizeSubsetEndpointsWithPBit(Bc7BlockType.Type6, block, ref scaledEp0,
				ref scaledEp1, ref pBit0, ref pBit1, startingVariation, partitionTable, subset, hasAlpha, hasAlpha);

			ep0 = Bc7EncodingHelpers.ExpandEndpoint(Bc7BlockType.Type6, scaledEp0, pBit0);
			ep1 = Bc7EncodingHelpers.ExpandEndpoint(Bc7BlockType.Type6, scaledEp1, pBit1);
			byte[] indices = new byte[16];
			Bc7EncodingHelpers.FillSubsetIndices(Bc7BlockType.Type6, block,
				ep0,
				ep1,
				partitionTable, subset, indices);

			

			if ((indices[0] & 0b1000) > 0) //If anchor index most significant bit is 1, switch endpoints
			{
				var c = scaledEp0;
				var p = pBit0;

				scaledEp0 = scaledEp1;
				pBit0 = pBit1;
				scaledEp1 = c;
				pBit1 = p;

				//redo indices
				ep0 = Bc7EncodingHelpers.ExpandEndpoint(Bc7BlockType.Type6, scaledEp0, pBit0);
				ep1 = Bc7EncodingHelpers.ExpandEndpoint(Bc7BlockType.Type6, scaledEp1, pBit1);
				Bc7EncodingHelpers.FillSubsetIndices(Bc7BlockType.Type6, block,
					ep0,
					ep1,
					partitionTable, subset, indices);
			}

			output.PackType6(new[]{
					new byte[]{scaledEp0.r, scaledEp0.g, scaledEp0.b, scaledEp0.a},
					new byte[]{scaledEp1.r, scaledEp1.g, scaledEp1.b, scaledEp1.a},
				},
				new[] { pBit0, pBit1 },
				indices);

			return output;
		}