Merge pull request #2414 from yuriks/texture-decode

Texture decoding cleanups

1 files changed, 60 insertions, 0 deletions

diff --git a/src/video_core/texture/texture_decode.h b/src/video_core/texture/texture_decode.h
new file mode 100644
index 000000000..5c636939a
--- /dev/null
+++ b/src/video_core/texture/texture_decode.h
@@ -0,0 +1,60 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+#include "common/vector_math.h"
+#include "video_core/pica.h"
+
+namespace Pica {
+namespace Texture {
+
+/// Returns the byte size of a 8*8 tile of the specified texture format.
+size_t CalculateTileSize(Pica::Regs::TextureFormat format);
+
+struct TextureInfo {
+    PAddr physical_address;
+    unsigned int width;
+    unsigned int height;
+    ptrdiff_t stride;
+    Pica::Regs::TextureFormat format;
+
+    static TextureInfo FromPicaRegister(const Pica::Regs::TextureConfig& config,
+                                        const Pica::Regs::TextureFormat& format);
+
+    /// Calculates stride from format and width, assuming that the entire texture is contiguous.
+    void SetDefaultStride() {
+        stride = Pica::Texture::CalculateTileSize(format) * (width / 8);
+    }
+};
+
+/**
+ * Lookup texel located at the given coordinates and return an RGBA vector of its color.
+ * @param source Source pointer to read data from
+ * @param x,y Texture coordinates to read from
+ * @param info TextureInfo object describing the texture setup
+ * @param disable_alpha This is used for debug widgets which use this method to display textures
+ * without providing a good way to visualize alpha by themselves. If true, this will return 255 for
+ * the alpha component, and either drop the information entirely or store it in an "unused" color
+ * channel.
+ * @todo Eventually we should get rid of the disable_alpha parameter.
+ */
+Math::Vec4<u8> LookupTexture(const u8* source, unsigned int x, unsigned int y,
+                             const TextureInfo& info, bool disable_alpha = false);
+
+/**
+ * Looks up a texel from a single 8x8 texture tile.
+ *
+ * @param source Pointer to the beginning of the tile.
+ * @param x, y In-tile coordinates to read from. Must be < 8.
+ * @param info TextureInfo describing the texture format.
+ * @param disable_alpha Used for debugging. Sets the result alpha to 255 and either discards the
+ *                      real alpha or inserts it in an otherwise unused channel.
+ */
+Math::Vec4<u8> LookupTexelInTile(const u8* source, unsigned int x, unsigned int y,
+                                 const TextureInfo& info, bool disable_alpha);
+
+} // namespace Texture
+} // namespace Pica