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/*
* PSn00bSDK basic graphics example
* (C) 2020-2023 Lameguy64, spicyjpeg - MPL licensed
*
* A comprehensive "advanced hello world" example showing how to set up the
* screen with double buffering, draw basic graphics (a bouncing square) and use
* PSn00bSDK's debug font API to quickly print some text, all while following
* best practices. This is not necessarily the simplest hello world example and
* may look daunting at first glance, but it is a good starting point for more
* complex programs.
*
* In order to avoid cluttering the program with global variables (as many Sony
* SDK examples and other PSn00bSDK examples written before this one do) two
* custom structures are employed:
*
* - a RenderBuffer structure containing the DISPENV and DRAWENV objects that
* represent the location of the framebuffer in VRAM, as well as the ordering
* table (OT) used to sort GPU commands/primitives by their Z index and the
* actual buffer commands will be written to;
* - a RenderContext structure holding two RenderBuffer instances plus some
* variables to keep track of which buffer is currently being drawn and how
* much of its primitive buffer has been filled up so far.
*
* A C++ version of this example is also available (see examples/hellocpp).
*/
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <psxgpu.h>
// Length of the ordering table, i.e. the range Z coordinates can have, 0-15 in
// this case. Larger values will allow for more granularity with depth (useful
// when drawing a complex 3D scene) at the expense of RAM usage and performance.
#define OT_LENGTH 16
// Size of the buffer GPU commands and primitives are written to. If the program
// crashes due to too many primitives being drawn, increase this value.
#define BUFFER_LENGTH 8192
/* Framebuffer/display list class */
typedef struct {
DISPENV disp_env;
DRAWENV draw_env;
uint32_t ot[OT_LENGTH];
uint8_t buffer[BUFFER_LENGTH];
} RenderBuffer;
typedef struct {
RenderBuffer buffers[2];
uint8_t *next_packet;
int active_buffer;
} RenderContext;
void setup_context(RenderContext *ctx, int w, int h, int r, int g, int b) {
// Place the two framebuffers vertically in VRAM.
SetDefDrawEnv(&(ctx->buffers[0].draw_env), 0, 0, w, h);
SetDefDispEnv(&(ctx->buffers[0].disp_env), 0, 0, w, h);
SetDefDrawEnv(&(ctx->buffers[1].draw_env), 0, h, w, h);
SetDefDispEnv(&(ctx->buffers[1].disp_env), 0, h, w, h);
// Set the default background color and enable auto-clearing.
setRGB0(&(ctx->buffers[0].draw_env), r, g, b);
setRGB0(&(ctx->buffers[1].draw_env), r, g, b);
ctx->buffers[0].draw_env.isbg = 1;
ctx->buffers[1].draw_env.isbg = 1;
// Initialize the first buffer and clear its OT so that it can be used for
// drawing.
ctx->active_buffer = 0;
ctx->next_packet = ctx->buffers[0].buffer;
ClearOTagR(ctx->buffers[0].ot, OT_LENGTH);
// Turn on the video output.
SetDispMask(1);
}
void flip_buffers(RenderContext *ctx) {
// Wait for the GPU to finish drawing, then wait for vblank in order to
// prevent screen tearing.
DrawSync(0);
VSync(0);
RenderBuffer *draw_buffer = &(ctx->buffers[ctx->active_buffer]);
RenderBuffer *disp_buffer = &(ctx->buffers[ctx->active_buffer ^ 1]);
// Display the framebuffer the GPU has just finished drawing and start
// rendering the display list that was filled up in the main loop.
PutDispEnv(&(disp_buffer->disp_env));
DrawOTagEnv(&(draw_buffer->ot[OT_LENGTH - 1]), &(draw_buffer->draw_env));
// Switch over to the next buffer, clear it and reset the packet allocation
// pointer.
ctx->active_buffer ^= 1;
ctx->next_packet = disp_buffer->buffer;
ClearOTagR(disp_buffer->ot, OT_LENGTH);
}
void *new_primitive(RenderContext *ctx, int z, size_t size) {
// Place the primitive after all previously allocated primitives, then
// insert it into the OT and bump the allocation pointer.
RenderBuffer *buffer = &(ctx->buffers[ctx->active_buffer]);
uint8_t *prim = ctx->next_packet;
addPrim(&(buffer->ot[z]), prim);
ctx->next_packet += size;
// Make sure we haven't yet run out of space for future primitives.
assert(ctx->next_packet <= &(buffer->buffer[BUFFER_LENGTH]));
return (void *) prim;
}
// A simple helper for drawing text using PSn00bSDK's debug font API. Note that
// FntSort() requires the debug font texture to be uploaded to VRAM beforehand
// by calling FntLoad().
void draw_text(RenderContext *ctx, int x, int y, int z, const char *text) {
RenderBuffer *buffer = &(ctx->buffers[ctx->active_buffer]);
ctx->next_packet = (uint8_t *)
FntSort(&(buffer->ot[z]), ctx->next_packet, x, y, text);
assert(ctx->next_packet <= &(buffer->buffer[BUFFER_LENGTH]));
}
/* Main */
#define SCREEN_XRES 320
#define SCREEN_YRES 240
int main(int argc, const char **argv) {
// Initialize the GPU and load the default font texture provided by
// PSn00bSDK at (960, 0) in VRAM.
ResetGraph(0);
FntLoad(960, 0);
// Set up our rendering context.
RenderContext ctx;
setup_context(&ctx, SCREEN_XRES, SCREEN_YRES, 63, 0, 127);
int x = 0, y = 0;
int dx = 1, dy = 1;
for (;;) {
// Update the position and velocity of the bouncing square.
if (x < 0 || x > (SCREEN_XRES - 64))
dx = -dx;
if (y < 0 || y > (SCREEN_YRES - 64))
dy = -dy;
x += dx;
y += dy;
// Draw the square by allocating a TILE (i.e. untextured solid color
// rectangle) primitive at Z = 1.
TILE *tile = (TILE *) new_primitive(&ctx, 1, sizeof(TILE));
setTile(tile);
setXY0 (tile, x, y);
setWH (tile, 64, 64);
setRGB0(tile, 255, 255, 0);
// Draw some text in front of the square (Z = 0, primitives with higher
// Z indices are drawn first).
draw_text(&ctx, 8, 16, 0, "Hello world!");
flip_buffers(&ctx);
}
return 0;
}
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