From 760c4972dc4d8ad062e7c21265223fde3847a849 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20Czekan=CC=81ski?= <ja.czekanski@gmail.com>
Date: Wed, 23 Dec 2020 00:12:41 +0100
Subject: [PATCH] animated-triangle: double buffering test

---
 Makefile                       |   1 +
 README.md                      |   1 +
 common-test.mk                 |   2 +-
 gpu/animated-triangle/Makefile |   3 +
 gpu/animated-triangle/main.c   | 132 +++++++++++++++++++++++++++++++++
 5 files changed, 138 insertions(+), 1 deletion(-)
 create mode 100644 gpu/animated-triangle/Makefile
 create mode 100644 gpu/animated-triangle/main.c

diff --git a/Makefile b/Makefile
index d1ebc35..aaf7544 100644
--- a/Makefile
+++ b/Makefile
@@ -11,6 +11,7 @@ IMAGES = common \
 		dma/chopping \
 		dma/dpcr \
 		dma/otc-test \
+		gpu/animated-triangle \
 		gpu/bandwidth \
 		gpu/benchmark \
 		gpu/clipping \
diff --git a/README.md b/README.md
index 1a0b6c0..bdbcf56 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,7 @@ otc-test                 | DMA Channel 6 (OTC aka Ordering Table clear) unit tes
 
 Name                     | Description
 -------------------------|------------
+animated-triangle        | Double buffered rotating triangle
 bandwidth                | Measure GPU/VRAM bandwidth
 benchmark                | GPU test to benchmark rasterizer for various commands
 clut-cache               | CLUT (Palette) cache behavior test
diff --git a/common-test.mk b/common-test.mk
index cf7b6d4..1de8668 100644
--- a/common-test.mk
+++ b/common-test.mk
@@ -3,7 +3,7 @@ include $(BASEDIR)/common.mk
 
 INCLUDE	    += -I$(realpath $(BASEDIR)/common)
 LIBDIRS		+= -L$(realpath $(BASEDIR)/common)
-LIBS        += -lcommon -lpsxgpu -lpsxetc -lpsxapi  -lc
+LIBS        += -lcommon -lpsxgpu -lpsxetc -lpsxsio -lpsxapi -lpsxgte -lc
 
 TARGET_EXE  := $(TARGET:.elf=.exe)
 
diff --git a/gpu/animated-triangle/Makefile b/gpu/animated-triangle/Makefile
new file mode 100644
index 0000000..e546223
--- /dev/null
+++ b/gpu/animated-triangle/Makefile
@@ -0,0 +1,3 @@
+TARGET = animated-triangle.elf
+
+include ../../common-test.mk
diff --git a/gpu/animated-triangle/main.c b/gpu/animated-triangle/main.c
new file mode 100644
index 0000000..8930976
--- /dev/null
+++ b/gpu/animated-triangle/main.c
@@ -0,0 +1,132 @@
+#include <common.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <psxgpu.h>
+#include <psxgte.h>
+#include <psxpad.h>
+
+int SCR_W = 320;
+int SCR_H = 240;
+#define OT_LEN  2
+
+static DISPENV disp[2];
+static DRAWENV draw[2];
+
+char pribuff[2][2048];			/* Primitive packet buffers */
+unsigned int ot[2][OT_LEN];		/* Ordering tables */
+char *nextpri;					/* Pointer to next packet buffer offset */
+int dbActive;
+
+int angle = 0;
+
+// Init function
+void init(void) {
+	ResetGraph(0);
+    SetVideoMode(MODE_NTSC);
+		
+    SetDefDispEnv(&disp[0], 0,     0, SCR_W, SCR_H);
+    SetDefDrawEnv(&draw[0], SCR_W, 0, SCR_W, SCR_H);
+
+    SetDefDrawEnv(&draw[1], 0,     0, SCR_W, SCR_H);
+    SetDefDispEnv(&disp[1], SCR_W, 0, SCR_W, SCR_H);
+	
+    for (int i = 0; i<2; i++){
+	    setRGB0(&draw[i], 255, 255, 255);
+	    draw[i].isbg = 1;
+    }
+
+	// Clear double buffer counter
+	dbActive = 0;
+	
+	// Apply the GPU environments
+	PutDispEnv(&disp[dbActive]);
+	PutDrawEnv(&draw[dbActive]);
+
+    ClearOTagR( ot[0], OT_LEN );
+    ClearOTagR( ot[1], OT_LEN );
+    nextpri = pribuff[dbActive];	
+}
+
+// Display function
+void display(void)
+{
+	DrawSync(0);
+	VSync(0);
+
+	dbActive = !dbActive;
+    nextpri = pribuff[dbActive];	
+    ClearOTagR( ot[dbActive], OT_LEN );
+
+	PutDrawEnv(&draw[dbActive]);
+	PutDispEnv(&disp[dbActive]);
+
+    SetDispMask(1);
+    DrawOTag(ot[1-dbActive] + OT_LEN-1);
+}
+
+struct Vertex {
+    int x, y;
+};
+
+void translate(struct Vertex* v, struct Vertex tr) {
+    v->x += tr.x;
+    v->y += tr.y;
+}
+
+void rot2d(struct Vertex* v, int angle) {
+    #define M_PI 3.14
+    int x = v->x;
+    int y = v->y;
+
+    int c = icos(angle);
+    int s = isin(angle);
+    
+    v->x = (x * c - y * s )>>12;
+    v->y = (x * s + y * c )>>12;
+}
+
+void drawTriangle(int cx, int cy, int size)
+{
+    struct Vertex v[3];
+    v[0].x = -0.866f * size; v[0].y = -0.5f * size;
+    v[1].x = 0.866f * size; v[1].y = -0.5f * size;
+    v[2].x = 0;         v[2].y = size;
+
+    struct Vertex tr = {
+        .x = cx,
+        .y = cy
+    };
+    for (int i = 0; i<3; i++) {
+        rot2d(&v[i], angle);
+        translate(&v[i], tr);
+    }
+
+    POLY_G3* p = (POLY_G3*)nextpri;
+    setPolyG3(p);
+    setRGB0(p, 255, 0, 0);
+    setRGB1(p, 0, 255, 0);
+    setRGB2(p, 0, 0, 255);
+    setXY3(p,
+        v[0].x, v[0].y,
+        v[1].x, v[1].y,
+        v[2].x, v[2].y
+    );
+    addPrim(ot[dbActive] + (OT_LEN-1), p);
+
+    nextpri += sizeof(POLY_G3);
+
+    angle += 4096/360;
+    if (angle >=4096) angle = 0;
+}
+
+int main(){
+    init();
+    printf("\ngpu/animated-triangle\n");
+
+    for (;;) {
+        drawTriangle(SCR_W/2, SCR_H/2, SCR_H/2);        
+
+        display();
+    }
+    return 0;
+}