gpu/triangle drawing test

Makefile

@@ -4,6 +4,7 @@ IMAGES = gpu/bandwidth \
 		gpu/benchmark \
 		gpu/quad \
 		gpu/transparency \
+		gpu/triangle \
 		gpu/lines \
 		gpu/rectangles \
 		gpu/texture-overflow \

README.md

@@ -10,6 +10,7 @@ gpu/bandwidth        | Measure GPU/VRAM bandwidth
 gpu/benchmark        | Simple GPU test to benchmark rasteriser
 gpu/quad             | Semi-transparent polygon commands - for testing fill rules and transparency handling
 gpu/transparency     | Draws rectangles with 4 semi-transparent blending modes
+gpu/triangle         | Draws Gouroud shaded equilateral triangle 
 gpu/lines            | Draws lines using different modes - for verifying Bresenham implementation, color blending, polyline handling
 gpu/rectangles       | Draws all combinations of Rectangle commands
 gpu/texture-overflow | Draws textured rectangle with UV overflowing VRAM width

gpu/triangle/Makefile

@@ -0,0 +1,4 @@
+include $(PSN00BSDK)/sdk-common.mk
+
+TARGET = triangle.elf
+LIBS  += -lpsxapi

gpu/triangle/main.c

@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <psxgpu.h>
+
+DISPENV disp;
+DRAWENV draw;
+
+#define SCR_W 320
+#define SCR_H 240
+
+#define SQRT3_2 0.866025f
+
+void setResolution(int w, int h)
+{
+    SetDefDispEnv(&disp, 0, 0, w, h);
+    SetDefDrawEnv(&draw, 0, 0, 1024, 512);
+
+    PutDispEnv(&disp);
+    PutDrawEnv(&draw);
+}
+
+void initVideo()
+{
+    ResetGraph(0);
+    setResolution(SCR_W, SCR_H);
+    SetDispMask(1);
+}
+
+void clearScreen()
+{
+    FILL f;
+    setFill(&f);
+    setRGB0(&f, 0xff, 0xff, 0xff);
+    setXY0(&f, 0, 0);
+    setWH(&f, 1023, 256);
+
+    DrawPrim(&f);
+
+    setXY0(&f, 0, 256);
+    setWH(&f, 1023, 256);
+
+    DrawPrim(&f);
+}
+
+void drawTriangle(int cx, int cy, int a)
+{
+    float h = a * SQRT3_2;
+
+    int x[3], y[3];
+    x[0] = cx - a / 2; y[0] = cy + h / 2;
+    x[1] = cx + a / 2; y[1] = cy + h / 2;
+    x[2] = cx;         y[2] = cy - h / 2;
+
+    POLY_G3 p;
+    setPolyG3(&p);
+    setRGB0(&p, 255, 0, 0);
+    setRGB1(&p, 0, 255, 0);
+    setRGB2(&p, 0, 0, 255);
+    setXY3(&p,
+        x[0], y[0],
+        x[1], y[1],
+        x[2], y[2]
+    );
+    DrawPrim(&p);
+}
+
+void setDithering(int dithering) 
+{
+    DR_TPAGE e;
+    unsigned short texpage = getTPage(/* bitcount - do not care */0, /* semi-transparency mode */ 0, /*x*/0, /*y*/0);
+    setDrawTPage(&e, /* Drawing to display area */ 1, dithering, texpage);
+    DrawPrim(&e);
+}
+
+int main()
+{
+    initVideo();
+    printf("\ngpu/triangle (shading test)\n");
+
+    for (;;)
+    {
+        clearScreen();
+
+        setDithering(0);
+        drawTriangle(SCR_W/2, SCR_H/2, 240);        
+        drawTriangle(768, 256, 500);
+
+        setDithering(1);
+        drawTriangle(SCR_W/2, SCR_H + SCR_H/2, 240);      
+
+        VSync(0);
+    }
+    return 0;
+}