1 files changed, 122 insertions, 1 deletions

diff --git a/src/libui_sdl/main_shaders.h b/src/libui_sdl/main_shaders.h
index dcf79d9..b602013 100644
--- a/src/libui_sdl/main_shaders.h
+++ b/src/libui_sdl/main_shaders.h
@@ -24,6 +24,7 @@ const char* kScreenVS = R"(#version 420
 layout(std140, binding=0) uniform uConfig
 {
     vec2 uScreenSize;
+    uint u3DScale;
     uint uFilterMode;
 };
 
@@ -50,10 +51,12 @@ const char* kScreenFS = R"(#version 420
 layout(std140, binding=0) uniform uConfig
 {
     vec2 uScreenSize;
+    uint u3DScale;
     uint uFilterMode;
 };
 
 layout(binding=0) uniform usampler2D ScreenTex;
+layout(binding=1) uniform sampler2D _3DTex;
 
 smooth in vec2 fTexcoord;
 
@@ -63,9 +66,127 @@ void main()
 {
     uvec4 pixel = texelFetch(ScreenTex, ivec2(fTexcoord), 0);
 
+    // bit0-13: BLDCNT
+    // bit14-15: DISPCNT display mode
+    // bit16-20: EVA
+    // bit21-25: EVB
+    // bit26-30: EVY
+    uvec4 ctl = texelFetch(ScreenTex, ivec2(256*3, int(fTexcoord.y)), 0);
+    uint dispmode = (ctl.g >> 6) & 0x3;
+
+    if (dispmode == 1)
+    {
+        uint eva = ctl.b & 0x1F;
+        uint evb = (ctl.b >> 5) | ((ctl.a & 0x03) << 3);
+        uint evy = ctl.a >> 2;
+
+        uvec4 top = pixel;
+        uvec4 mid = texelFetch(ScreenTex, ivec2(fTexcoord) + ivec2(256,0), 0);
+        uvec4 bot = texelFetch(ScreenTex, ivec2(fTexcoord) + ivec2(512,0), 0);
+
+        uint winmask = top.b >> 7;
+
+        if ((top.a & 0x40) != 0)
+        {
+            float xpos = top.r + fract(fTexcoord.x);
+            uvec4 _3dpix = uvec4(texelFetch(_3DTex, ivec2(vec2(xpos, fTexcoord.y)*u3DScale), 0).bgra
+                         * vec4(63,63,63,31));
+
+            if (_3dpix.a > 0) { top = _3dpix; top.a |= 0x40; bot = mid; }
+            else              top = mid;
+        }
+        else if ((mid.a & 0x40) != 0)
+        {
+            float xpos = mid.r + fract(fTexcoord.x);
+            uvec4 _3dpix = uvec4(texelFetch(_3DTex, ivec2(vec2(xpos, fTexcoord.y)*u3DScale), 0).bgra
+                         * vec4(63,63,63,31));
+
+            if (_3dpix.a > 0) { bot = _3dpix; bot.a |= 0x40; }
+        }
+        else
+        {
+            // conditional texture fetch no good for performance, apparently
+            //texelFetch(_3DTex, ivec2(0, fTexcoord.y*2), 0);
+            bot = mid;
+        }
+
+        top.b &= 0x3F;
+        bot.b &= 0x3F;
+
+        uint target2;
+        if      ((bot.a & 0x80) != 0) target2 = 0x10;
+        else if ((bot.a & 0x40) != 0) target2 = 0x01;
+        else                          target2 = bot.a;
+        bool t2pass = ((ctl.g & target2) != 0);
+
+        uint coloreffect = 0;
+
+        if ((top.a & 0x80) != 0 && t2pass)
+        {
+            // sprite blending
+
+            coloreffect = 1;
+
+            if ((top.a & 0x40) != 0)
+            {
+                eva = top.a & 0x1F;
+                evb = 16 - eva;
+            }
+        }
+        else if ((top.a & 0x40) != 0 && t2pass)
+        {
+            // 3D layer blending
+
+            coloreffect = 4;
+            eva = (top.a & 0x1F) + 1;
+            evb = 32 - eva;
+        }
+        else
+        {
+            if      ((top.a & 0x80) != 0) top.a = 0x10;
+            else if ((top.a & 0x40) != 0) top.a = 0x01;
+
+            if ((ctl.r & top.a) != 0 && winmask != 0)
+            {
+                uint effect = ctl.r >> 6;
+                if ((effect != 1) || t2pass) coloreffect = effect;
+            }
+        }
+
+        if (coloreffect == 0)
+        {
+            pixel = top;
+        }
+        else if (coloreffect == 1)
+        {
+            pixel = ((top * eva) + (bot * evb)) >> 4;
+            pixel = min(pixel, 0x3F);
+        }
+        else if (coloreffect == 2)
+        {
+            pixel = top;
+            pixel += ((uvec4(0x3F,0x3F,0x3F,0) - pixel) * evy) >> 4;
+        }
+        else if (coloreffect == 3)
+        {
+            pixel = top;
+            pixel -= (pixel * evy) >> 4;
+        }
+        else
+        {
+            pixel = ((top * eva) + (bot * evb)) >> 5;
+            if (eva <= 16) pixel += uvec4(1,1,1,0);
+            pixel = min(pixel, 0x3F);
+        }
+    }
+
+    pixel.rgb <<= 2;
+    pixel.rgb |= (pixel.rgb >> 6);
+
     // TODO: filters
 
-    oColor = vec4(vec3(pixel.bgr) / 255.0, 1.0);
+    oColor = vec4(vec3(pixel.rgb) / 255.0, 1.0);
+    //oColor = texelFetch(_3DTex, ivec2(fTexcoord*4), 0).bgra;
 }
 )";