attempted to add blending and fix overlapping triangle seam

Author: MCRcortex

src/main/java/me/cortex/voxy/client/core/model/bakery/SoftwareRasterizer.java

@@ -1,6 +1,9 @@
 package me.cortex.voxy.client.core.model.bakery;
 
 import me.cortex.voxy.client.core.model.ModelFactory;
+import net.caffeinemc.mods.sodium.api.util.ColorABGR;
+import net.caffeinemc.mods.sodium.api.util.ColorARGB;
+import net.caffeinemc.mods.sodium.api.util.ColorMixer;
 import org.joml.Matrix4f;
 import org.joml.Vector3f;
 import org.joml.Vector4f;
@@ -92,18 +95,17 @@ private void rasterQuad(Matrix4f transform, long addr) {
         this.a1.set(this.qmuv1);
         this.a2.set(this.qmuv2);
         this.a3.set(this.qmuv3);
-        this.rasterTriangle();
+        this.rasterTriangle(false);
         this.scratchR1.set(this.scratch3);
         this.scratchR2.set(this.scratch4);
         this.scratchR3.set(this.scratch1);
         this.a1.set(this.qmuv3);
         this.a2.set(this.qmuv4);
         this.a3.set(this.qmuv1);
-        this.rasterTriangle();
-
+        this.rasterTriangle(true);
     }
 
-    private void rasterTriangle() {
+    private void rasterTriangle(boolean orZero) {
         Vector3f v1 = this.scratchR1;
         Vector3f v2 = this.scratchR2;
         Vector3f v3 = this.scratchR3;
@@ -142,7 +144,7 @@ private void rasterTriangle() {
                 float w1 = edge(v2, v3, cx, cy)*invArea;
                 float w2 = edge(v3, v1, cx, cy)*invArea;
                 float w3 = 1.0f-w1-w2;
-                if (w1>=0.0f&&w2>=0.0f&&w3>=0.0f) {
+                if ((w1>0.0f&&w2>0.0f&&w3>0.0f)||(orZero&&w1>=0.0f&&w2>=0.0f&&w3>=0.0f)) {
                     //Dont need to worry about perspective correction afak as it should already be all correct
 
                     //pixel is inside the triangle
@@ -193,17 +195,39 @@ private void rasterPixel(int index, float b1, float b2, float b3) {//Barry coord
         int srcColour = (int) this.framebuffer[index];
         this.framebuffer[index] &= ~Integer.toUnsignedLong(-1);
 
-        //When blending is enabled do this
-        // ARBDrawBuffersBlend.glBlendFuncSeparateiARB(0, GL_ONE_MINUS_DST_ALPHA, GL_DST_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
         if (this.doTheBlending) {//Blending
             //mutate colour var
+            colour = doBlending(srcColour, colour);
         }
 
 
         //Remember ABGR FORMAT
         this.framebuffer[index] |= Integer.toUnsignedLong(colour);
     }
 
+
+    // ARBDrawBuffersBlend.glBlendFuncSeparateiARB(0, GL_ONE_MINUS_DST_ALPHA, GL_DST_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+    private static int doBlending(int scr, int dst) {
+        int srcAlpha = (scr>>>24)&0xFF;
+        if (srcAlpha == 0) {
+            return dst;
+        }
+        int dstAlpha = (dst>>>24)&0xFF;
+        scr &= ~(0xFF<<24);
+        dst &= ~(0xFF<<24);
+        int blendAlpha = Math.min(0xFF,srcAlpha+((dstAlpha*(255-srcAlpha))>>8));
+        //how much did we actually get
+
+        int blend = ColorMixer.mix(dst, scr, dstAlpha);//addRGB(ColorABGR.mulRGB(scr, 255-dstAlpha),ColorABGR.mulRGB(dst, dstAlpha));
+        return blend|(blendAlpha<<24);
+    }
+
+    private static int addRGB(int a, int b) {
+        return Math.min(0xFF,(a&0xFF)+(b&0xFF))|
+                Math.min((0xFF<<8),(a&(0xFF<<8))+(b&(0xFF<<8)))|
+                Math.min((0xFF<<16),(a&(0xFF<<16))+(b&(0xFF<<16)));
+    }
+
     private static float edge(Vector3f a, Vector3f b, Vector3f c) {
         return (c.x-a.x)*(b.y-a.y) - (c.y-a.y) * (b.x-a.x);
     }