vxKernel/src/modules/display/draw/dpixel.c

#include <vhex/display.h>
#include <vhex/defs/attributes.h>
#include <vhex/defs/types.h>

//---
// Kernel-level API
//---

/* dpixel_render() : drawing algorithm */
void dpixel_render(dsurface_t *surface, int x, int y, int color)
{
	if (color == C_NONE)
		return;

	/* check point culling */
	if (y < surface->y1
		|| x < surface->x1
		|| y > surface->y2
		|| x > surface->x2) {
		return;
	}

	/* calculate the draw index */
	int real_y   = (y - surface->y1) * surface->width;
	int real_x   = (x - surface->x1);
	int draw_idx = real_y + real_x;

	/* handle special color */
	uint16_t *vram = surface->vram;
	if (color == C_INVERT)
		color = vram[draw_idx] ^ 0xffff;

	/* set the pixel */
	vram[draw_idx] = color;
}

//---
// Dstack-level API
//---

/* dpixel_render_dstack() : dstack-API compatible render */
void dpixel_dstack(dsurface_t *surface, uint32_t *arg)
{
	dpixel_render(surface, arg[0], arg[1], arg[2]);
}

//---
// User-level API
//---

/* dpixel() : draw a pixel in screen */
void dpixel(int x, int y, int color)
{
	dstack_add_action(
		&DSTACK_CALL(&dpixel_dstack, x, y, color),
		NULL,
		NULL
	);
}