// Renderer: 2D primitives that operate on the software framebuffer
// and the colour state shared with the scenery interpreter.

#ifndef RENDERER_H
#define RENDERER_H

#include "framebuffer.h"
#include "palette.h"
#include "types.h"

// Active framebuffer / colour state. The scenery VM reads these so
// individual opcodes need only set the colour and call the line or
// span primitives. `hiresColor` is the chunk5 ToHiresColorTable code
// (HIRES_BLACK1 / HIRES_VIOLET / HIRES_GREEN / HIRES_WHITE1 etc.) the
// hires bitplane primitives use. `drawColor` stays the legacy palette
// index for the panel-area renderers that haven't moved to the
// bitplane yet.
typedef struct RenderStateT {
        FramebufferT *fb;
        ColorE       fillColor;
        ColorE       altFillColor;
        ColorE       drawColor;
        uint8_t      hiresColor;
        uint8_t      hiresFill;
        uint8_t      hiresAltFill;
} RenderStateT;

void rendererBegin(RenderStateT *state, FramebufferT *fb);
void rendererSetDrawColor(RenderStateT *state, ColorE color);
void rendererSetHiresColor(RenderStateT *state, uint8_t hiresCode);
void rendererSetFillColors(RenderStateT *state, ColorE fill, ColorE altFill);
void rendererSwapFillColors(RenderStateT *state);

void rendererDrawLine(RenderStateT *state, int16_t x1, int16_t y1, int16_t x2, int16_t y2);

// Horizontal color-pixel span at color-column space (0..139).
// `xRight` is the rightmost color column, walking leftward for `length+1`
// pixels. Mirrors chunk5's DrawColorSpan ($78E0). Used by the polygon
// scan-line fill (chunk5.s L7826+).
void rendererDrawColorSpan(RenderStateT *state, int16_t xRight, int16_t length, int16_t y);

// Scan-line fill of an arbitrary polygon. Vertices are color-pixel
// coordinates (xColor 0..139, y 0..191). Mirrors chunk5's L7724+
// polygon edge rasterizer that walks edges per row, sorts intersections,
// and emits paired DrawColorSpan calls. The current `hiresColor` is
// used as the fill color.
void rendererFillPolygon(RenderStateT *state, const int16_t *xs, const int16_t *ys, int count);
void rendererFillSkyAndGround(RenderStateT *state, int16_t horizonRow);

// Same idea as `rendererFillSkyAndGround` but the divide line is
// tilted by `bankSin`/`bankCos` (Q1.15: -32767..+32767, the
// `math6502Sin/Cos` output) and centred on `(horizonX, horizonY)`.
// Pixels strictly above the line use `altFillColor` (sky) and below
// use `fillColor` (ground).
void rendererFillTiltedSkyGround(RenderStateT *state, int16_t horizonX, int16_t horizonY, int16_t bankSin, int16_t bankCos);

// Draw a wing-strut / tail overlay over a side / rear viewport. FS2
// chunk3 DrawWingsOrTail fills a trapezoid of color spans in a fixed
// pattern per view-direction; we render a filled triangle at the
// matching corner of the viewport so the player can see the wingtip
// in F2/F4, vertical fin in F3, wheel well in F5.
//   viewDir : 0=FORWARD, 1=RIGHT, 2=BACK, 3=LEFT, 4=DOWN (matches
//             ViewDirectionE in aircraft.h)
// FORWARD draws nothing.
void rendererDrawWingOverlay(RenderStateT *state, int viewDir);

#endif