1 files changed, 141 insertions, 2 deletions
diff --git a/GPU3D_Soft.cpp b/GPU3D_Soft.cpp
index 38d3539..9c057e9 100644
--- a/GPU3D_Soft.cpp
+++ b/GPU3D_Soft.cpp
@@ -32,7 +32,7 @@ u8 ColorBuffer[256*192 * 4];
 
 bool Init()
 {
-    //
+    return true;
 }
 
 void DeInit()
@@ -46,9 +46,148 @@ void Reset()
 }
 
 
+void RenderPolygon(Polygon* polygon)
+{
+    int nverts = polygon->NumVertices;
+
+    int vtop, vbot;
+    s32 ytop = 191, ybot = 0;
+    s32 scrcoords[10][3];
+
+    // find the topmost and bottommost vertices of the polygon
+
+    for (int i = 0; i < nverts; i++)
+    {
+        Vertex* vtx = polygon->Vertices[i];
+
+        s32 scrX = (((vtx->Position[0] + 0x1000) * Viewport[2]) >> 13) + Viewport[0];
+        s32 scrY = (((vtx->Position[1] + 0x1000) * Viewport[3]) >> 13) + Viewport[1];
+        if (scrX > 255) scrX = 255;
+        if (scrY > 191) scrY = 191;
+
+        scrcoords[i][0] = scrX;
+        scrcoords[i][1] = 191 - scrY;
+        scrcoords[i][2] = 0; // TODO: Z
+
+        if (scrcoords[i][1] < ytop)
+        {
+            ytop = scrcoords[i][1];
+            vtop = i;
+        }
+        if (scrcoords[i][1] > ybot)
+        {
+            ybot = scrcoords[i][1];
+            vbot = i;
+        }
+    }
+
+    // draw, line per line
+
+    int lcur = vtop, rcur = vtop;
+    int lnext, rnext;
+    s32 lstep, rstep;
+    //s32 xmin, xmax;
+
+    lnext = lcur + 1;
+    if (lnext >= nverts) lnext = 0;
+    rnext = rcur - 1;
+    if (rnext < 0) rnext = nverts - 1;
+
+    /*if ((scrcoords[lnext][1] - scrcoords[lcur][1]) == 0) lstep = 0; else
+    lstep = ((scrcoords[lnext][0] - scrcoords[lcur][0]) << 12) / (scrcoords[lnext][1] - scrcoords[lcur][1]);
+    if ((scrcoords[rnext][1] - scrcoords[rcur][1]) == 0) rstep = 0; else
+    rstep = ((scrcoords[rnext][0] - scrcoords[rcur][0]) << 12) / (scrcoords[rnext][1] - scrcoords[rcur][1]);*/
+
+    //xmin = scrcoords[lcur][0] << 12;
+    //xmax = scrcoords[rcur][0] << 12;
+
+    for (s32 y = ytop; y <= ybot; y++)
+    {
+        if (y == scrcoords[lnext][1] && y < ybot)
+        {
+            lcur++;
+            if (lcur >= nverts) lcur = 0;
+
+            lnext = lcur + 1;
+            if (lnext >= nverts) lnext = 0;
+
+            //lstep = ((scrcoords[lnext][0] - scrcoords[lcur][0]) << 12) / (scrcoords[lnext][1] - scrcoords[lcur][1]);
+            //xmin = scrcoords[lcur][0] << 12;
+        }
+
+        if (y == scrcoords[rnext][1] && y < ybot)
+        {
+            rcur--;
+            if (rcur < 0) rcur = nverts - 1;
+
+            rnext = rcur - 1;
+            if (rnext < 0) rnext = nverts - 1;
+
+            //rstep = ((scrcoords[rnext][0] - scrcoords[rcur][0]) << 12) / (scrcoords[rnext][1] - scrcoords[rcur][1]);
+            //xmax = scrcoords[rcur][0] << 12;
+        }
+
+        s32 lfactor, rfactor;
+
+        if (scrcoords[lnext][1] == scrcoords[lcur][1])
+            lfactor = 0;
+        else
+            lfactor = ((y - scrcoords[lcur][1]) << 12) / (scrcoords[lnext][1] - scrcoords[lcur][1]);
+
+        if (scrcoords[rnext][1] == scrcoords[rcur][1])
+            rfactor = 0;
+        else
+            rfactor = ((y - scrcoords[rcur][1]) << 12) / (scrcoords[rnext][1] - scrcoords[rcur][1]);
+
+        s32 xmin = scrcoords[lcur][0] + (((scrcoords[lnext][0] - scrcoords[lcur][0]) * lfactor) >> 12);
+        s32 xmax = scrcoords[rcur][0] + (((scrcoords[rnext][0] - scrcoords[rcur][0]) * rfactor) >> 12);
+
+        for (s32 x = xmin; x <= xmax; x++)
+        {
+            u8* pixel = &ColorBuffer[((256*y) + x) * 4];
+            pixel[0] = 0;
+            pixel[1] = 63;
+            pixel[2] = 0;
+            pixel[3] = 31;
+        }
+    }
+
+    // test
+    /*for (int i = 0; i < nverts; i++)
+    {
+        Vertex* vtx = polygon->Vertices[i];
+
+        s32 scrX = (((vtx->Position[0] + 0x1000) * Viewport[2]) >> 13) + Viewport[0];
+        s32 scrY = (((vtx->Position[1] + 0x1000) * Viewport[3]) >> 13) + Viewport[1];
+        if (scrX > 255) scrX = 255;
+        if (scrY > 191) scrY = 191;
+
+        u8* pixel = &ColorBuffer[((256*scrY) + scrX) * 4];
+        pixel[0] = 0;
+        pixel[1] = 63;
+        pixel[2] = 0;
+        pixel[3] = 31;
+    }*/
+}
+
 void RenderFrame(Vertex* vertices, Polygon* polygons, int npolys)
 {
-    //
+    // TODO: render translucent polygons last
+
+    for (int i = 0; i < 256*192; i++)
+    {
+        ((u32*)ColorBuffer)[i] = 0x1F000000;
+    }
+
+    for (int i = 0; i < npolys; i++)
+    {
+        RenderPolygon(&polygons[i]);
+    }
+}
+
+u8* GetLine(int line)
+{
+    return &ColorBuffer[line * 256 * 4];
 }
 
 }