From 0917cd39b79041326eae4ff0b337ed5130e1b2c7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miloslav=20=C4=8C=C3=AD=C5=BE?= <tastyfish@seznam.cz>
Date: Sat, 4 May 2019 23:04:13 +0200
Subject: [PATCH] Add rasterization tests

---
 test.c | 151 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 150 insertions(+), 1 deletion(-)

diff --git a/test.c b/test.c
index 72a4d8e..8c02963 100644
--- a/test.c
+++ b/test.c
@@ -2,8 +2,156 @@
 #define S3L_PIXEL_FUNCTION pixelFunc
 #include "s3l.h"
 
-void pixelFunc(S3L_PixelInfo *pixel)
+#define TEST_BUFFER_W 16
+#define TEST_BUFFER_H 16
+
+uint8_t testRaster[TEST_BUFFER_W * TEST_BUFFER_H];
+
+void pixelFunc(S3L_PixelInfo *p)
 {
+  testRaster[p->y * TEST_BUFFER_W + p->x] = 1;
+}
+
+uint16_t testTriangleRasterization(
+  S3L_ScreenCoord x0,
+  S3L_ScreenCoord y0,
+  S3L_ScreenCoord x1,
+  S3L_ScreenCoord y1,
+  S3L_ScreenCoord x2,
+  S3L_ScreenCoord y2,
+  uint8_t *expectedPixels
+  )
+{
+  printf("  --- testing tringle rasterization (|: expected, -: rasterized) ----\n");
+
+  S3L_DrawConfig conf;
+
+  conf.backfaceCulling = S3L_BACKFACE_CULLING_NONE;
+  conf.mode = S3L_MODE_TRIANGLES;
+
+  memset(testRaster,0,TEST_BUFFER_W * TEST_BUFFER_H);
+
+  S3L_drawTriangle(x0,y0,x1,y1,x2,y2,conf,0);
+  
+  printf("     0123456789ABCDEF\n");
+
+  uint16_t numErrors = 0;
+
+  for (uint8_t y = 0; y < TEST_BUFFER_H; ++y)
+  {
+    printf("  %d",y);
+    
+    if (y < 10)
+      printf(" ");
+
+    for (uint8_t x = 0; x < TEST_BUFFER_W; ++x)
+    {
+      uint8_t expected = expectedPixels[y * TEST_BUFFER_W + x];
+      uint8_t rasterized = testRaster[y * TEST_BUFFER_W + x];
+
+      char c =
+        expected ?
+          (rasterized ? '+' : '|')
+          :
+          (rasterized ? '-' : ' ');
+
+      if (c == '-' || c == '|')
+        numErrors++;
+
+      printf("%c",c);
+    }
+  
+    printf("\n");
+  }
+    
+  printf("  errors: %d\n\n",numErrors);
+
+  return numErrors;
+}
+
+uint16_t testRasterization()
+{
+  printf("\n=== TESTING RASTERIZATION ===\n");
+  
+  uint16_t numErrors = 0;
+
+  uint8_t pixels1[TEST_BUFFER_W * TEST_BUFFER_H] =
+  {
+  // 0 1 2 3 4 5 6 7 8 9 A B C D E F
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 1
+     0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0, // 2
+     0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0, // 3
+     0,0,0,1,1,1,1,0,0,0,0,0,0,0,0,0, // 4
+     0,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0, // 5
+     0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0, // 6
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 7
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 8
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 9
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // A
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // B
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // C
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // D
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // E
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0  // F
+  }; 
+
+  numErrors += testTriangleRasterization(4,1, 1,6, 9,7, pixels1);
+
+  uint8_t pixels2[TEST_BUFFER_W * TEST_BUFFER_H] =
+  {
+  // 0 1 2 3 4 5 6 7 8 9 A B C D E F
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0
+     0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0, // 2
+     0,0,1,1,1,1,0,0,0,0,0,0,0,0,0,0, // 3
+     0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0, // 4
+     0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0, // 5
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 6
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 7
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 8
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 9
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // A
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // B
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // C
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // D
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // E
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0  // F
+  }; 
+
+  numErrors += testTriangleRasterization(7,1, 1,2, 4,6, pixels2);
+
+  uint8_t pixels3[TEST_BUFFER_W * TEST_BUFFER_H] =
+  {
+  // 0 1 2 3 4 5 6 7 8 9 A B C D E F
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0
+     0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0
+     0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0, // 2
+     0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0, // 3
+     0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0, // 4
+     0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0, // 5
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 6
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 7
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 8
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 9
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // A
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // B
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // C
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // D
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // E
+     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0  // F
+  }; 
+
+  numErrors += testTriangleRasterization(2,1, 6,9, 1,3, pixels3);
+
+  uint8_t pixelsEmpty[TEST_BUFFER_W * TEST_BUFFER_H];
+  memset(pixelsEmpty,0,TEST_BUFFER_W * TEST_BUFFER_H);
+
+  numErrors += testTriangleRasterization(5,3, 3,3, 9,3, pixelsEmpty);
+  numErrors += testTriangleRasterization(9,4, 9,0, 9,9, pixelsEmpty);
+  numErrors += testTriangleRasterization(3,3, 6,6, 7,7, pixelsEmpty);
+
+  printf("total rasterization errors: %d\n",numErrors);
 }
 
 int main()
@@ -27,6 +175,7 @@ int main()
   S3L_mat4Xmat4(&m,&m2);
   S3L_writeMat4(m);
 
+  testRasterization();
 
   return 0;
 }