added semi-transparency test

Makefile

@@ -3,6 +3,7 @@ TOPTARGETS = build clean
 IMAGES = gpu/bandwidth \
 		gpu/benchmark \
 		gpu/quad \
+		gpu/transparency \
 		gte-fuzz \
 		spu/test \
 		spu/stereo \

README.md

@@ -2,15 +2,16 @@
 
 ## Tests
 
-Name          | Description
---------------|------------
-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
-gte-fuzz      | Executes GTE opcodes with random parameters, can be used to verify agains real console
-spu/test      | Check SPU behaviour (data is lost randomly on 32bit access, ok on 16bit)
-spu/stereo    | Play samples on first two voices 
-timers        | Run Timer0,1,2 using various clock sources and sync modes and time them using busy loops and vblank interrupt
+Name            | Description
+----------------|------------
+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
+gte-fuzz        | Executes GTE opcodes with random parameters, can be used to verify agains real console
+spu/test        | Check SPU behaviour (data is lost randomly on 32bit access, ok on 16bit)
+spu/stereo      | Play samples on first two voices 
+timers          | Run Timer0,1,2 using various clock sources and sync modes and time them using busy loops and vblank interrupt
 
 Note: Make sure your PS-EXE loaded does set default value for Stack Pointer - these .exes has SP set to 0.
 

gpu/transparency/Makefile

@@ -0,0 +1,3 @@
+include $(PSN00BSDK)/sdk-common.mk
+
+TARGET = transparency.elf

gpu/transparency/main.c

@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <psxgpu.h>
+#include <psxetc.h>
+
+DISPENV disp;
+DRAWENV draw;
+
+#define SCR_W 320
+#define SCR_H 240
+
+void setResolution(int w, int h) {
+    SetDefDispEnv(&disp, 0, 0, w, h);
+    SetDefDrawEnv(&draw, 0, 0, w, h);
+
+    PutDispEnv(&disp);
+    PutDrawEnv(&draw);
+}
+
+void initVideo()
+{
+    ResetGraph(0);
+    setResolution(SCR_W, SCR_H);
+    SetDispMask(1);
+}
+
+void fillRect(int x, int y, int w, int h, int r, int g, int b) {
+    FILL f;
+    setFill(&f);
+    setRGB0(&f, r, g, b);
+    setXY0(&f, x, y);
+    setWH(&f, w, h);
+
+    DrawPrim(&f);
+}
+
+void clearScreen() {
+    fillRect(0,   0,   512, 256, 0xff, 0xff, 0xff);
+    fillRect(512, 0,   512, 256, 0xff, 0xff, 0xff);
+    fillRect(0,   256, 512, 256, 0xff, 0xff, 0xff);
+    fillRect(512, 256, 0x3f1, 256, 0xff, 0xff, 0xff);
+}
+
+void setSemiTransparencyMode(int mode) {
+    DR_TPAGE e;
+    unsigned short texpage = getTPage(/* bitcount - do not card */0, /* semi-transparency mode */ mode, /*x*/0, /*y*/0);
+    setDrawTPage(&e, /* Drawing to display area */ 1, /* dithering */ 0, texpage);
+    DrawPrim(&e);
+}
+
+const unsigned char bgColors[4] = {
+    0, 64, 128, 255,
+};
+
+int main() {
+    initVideo();
+    printf("\ngpu/transparency\n");
+
+    clearScreen();
+
+    for (;;) {
+        // Fill screen with 4 strips of different shade
+        for (int i = 0; i<4; i++) {
+            fillRect(SCR_W/4 * i, 0, SCR_W/4, SCR_H, bgColors[i], bgColors[i], bgColors[i]);
+        }
+
+        // For every semi-transparency (blending) mode
+        for (int mode = 0; mode <= 3; mode++) {
+            setSemiTransparencyMode(mode);
+
+            // Draw semi transparent rectangles with different colors
+            for (int x = 0; x < 8 * 4; x++) {
+                const int S = 8;
+
+                int r = 128 * ((x>>0)&1);
+                int g = 128 * ((x>>1)&1);
+                int b = 128 * ((x>>2)&1);
+                int y = mode;
+
+                TILE t;
+                setTile(&t);
+                setSemiTrans(&t, 1);
+                setRGB0(&t, r, g, b);
+                setXY0(&t, 1 + (S+2) * x, 64 + (S+16) * y);
+                setWH(&t, S, S);
+
+                DrawPrim(&t);
+            }
+        }
+
+        VSync(0);
+    }
+    return 0;
+}