#include "afterburner.h"
#include <azur/gint/render.h>
#include <num/num.h>
#include <math.h>
using namespace libnum;

uint8_t AB_HORIZON_SHADER_ID = -1;

struct ab_horizon_cmd
{
    /* Shader ID for Azur */
    uint8_t shader_id;
    uint8_t _[3];

    /* Variation in value for a single move of +1x */
    num dx;
    /* Variation in value for a row move of -198x and +1y */
    num drow;
    /* Palette, supporting indexes 0...255 */
    uint16_t *palette;
    /* Current horizon value */
    num current;
};

extern "C" {
    extern azrp_shader_t ab_horizon_shader;
}

GCONSTRUCTOR
static void register_shader(void)
{
    AB_HORIZON_SHADER_ID = azrp_register_shader(ab_horizon_shader);
}

void ab_horizon(int cx, int cy, float alpha, uint16_t *palette)
{
    prof_enter(azrp_perf_cmdgen);

    num sin_alpha = sinf(alpha);
    num cos_alpha = cosf(alpha);

    num dx = -sin_alpha;
    num dy = -cos_alpha;

    struct ab_horizon_cmd cmd;
    cmd.shader_id = AB_HORIZON_SHADER_ID;
    cmd.current = dx * -cx + dy *-cy;
    cmd.dx = dx;
    cmd.drow = -198*dx + dy;
    cmd.palette = palette;

    azrp_queue_command(&cmd, sizeof cmd, 0, azrp_frag_count);
    prof_leave(azrp_perf_cmdgen);
}

void ab_horizon_configure(void)
{
    uint32_t value = (azrp_width << 16) | azrp_frag_height;
    azrp_set_uniforms(AB_HORIZON_SHADER_ID, (void *)value);
}