testpat: cleanup and fix drawing yuv pixels

diff --git a/libkmstest/testpat.cpp b/libkmstest/testpat.cpp
index 5c6766045a935ccc4c7b34c35ef2dc8e48ec66eb..f65a1f87bd35eed5bc99a1ac0d220b612d7d72da 100644 (file)
--- a/libkmstest/testpat.cpp
+++ b/libkmstest/testpat.cpp
@@ -18,8 +18,6 @@ namespace kms
 {
 static void draw_pixel(DumbFramebuffer& buf, unsigned x, unsigned y, RGB color)
 {
-       static RGB c1;
-
        switch (buf.format()) {
        case PixelFormat::XRGB8888:
        {
@@ -44,43 +42,55 @@ static void draw_pixel(DumbFramebuffer& buf, unsigned x, unsigned y, RGB color)
        case PixelFormat::YVYU:
        case PixelFormat::VYUY:
        {
+               // HACK. we store the even pixels to c1, and only draw when at the odd pixel.
+
+               static RGB c1;
+
                if ((x & 1) == 0) {
                        c1 = color;
                        return;
                }
 
+               // adjust X back to the even pixel
+               x--;
+
                uint8_t *p = (uint8_t*)(buf.map(0) + buf.stride(0) * y + x * 2);
 
                YUV yuv1 = c1.yuv();
                YUV yuv2 = color.yuv();
 
+               uint8_t y0 = yuv1.y;
+               uint8_t y1 = yuv2.y;
+               uint8_t u = (yuv1.u + yuv2.u) / 2;
+               uint8_t v = (yuv1.v + yuv2.v) / 2;
+
                switch (buf.format()) {
                case PixelFormat::UYVY:
-                       p[0] = (yuv1.u + yuv2.u) / 2;
-                       p[1] = yuv1.y;
-                       p[2] = (yuv1.v + yuv2.v) / 2;
-                       p[3] = yuv2.y;
+                       p[0] = u;
+                       p[1] = y0;
+                       p[2] = v;
+                       p[3] = y1;
                        break;
 
                case PixelFormat::YUYV:
-                       p[0] = yuv1.y;
-                       p[1] = (yuv1.u + yuv2.u) / 2;
-                       p[2] = yuv2.y;
-                       p[3] = (yuv1.v + yuv2.v) / 2;
+                       p[0] = y0;
+                       p[1] = u;
+                       p[2] = y1;
+                       p[3] = v;
                        break;
 
                case PixelFormat::YVYU:
-                       p[0] = yuv1.y;
-                       p[1] = (yuv1.v + yuv2.v) / 2;
-                       p[2] = yuv2.y;
-                       p[3] = (yuv1.u + yuv2.u) / 2;
+                       p[0] = y0;
+                       p[1] = v;
+                       p[2] = y1;
+                       p[3] = u;
                        break;
 
                case PixelFormat::VYUY:
-                       p[0] = (yuv1.v + yuv2.v) / 2;
-                       p[1] = yuv1.y;
-                       p[2] = (yuv1.u + yuv2.u) / 2;
-                       p[3] = yuv2.y;
+                       p[0] = v;
+                       p[1] = y0;
+                       p[2] = u;
+                       p[3] = y1;
                        break;
                default:
                        break;