VideoDriver.h

/****************************************************************************
 * Platform Abstraction Layer
 * Daryl Borth 2026
 * VideoDriver.h
 *
 * Platform video backend GuiImage and GuiText delegates to. Exactly one driver
 * implements this and assigns the single global instance below
 ***************************************************************************/
#pragma once
 
#include <stdint.h>
#include <stddef.h>
#include <ft2build.h>
#include FT_FREETYPE_H
#include "Mesh.h"
 
// PixelColor and MeshVertex live in Mesh.h so host builds can use them without FreeType
 
class ImageRenderer;
class GlyphRenderer;

class VideoDriver
{
    public:
        virtual ~VideoDriver() = default;

        virtual void init(int width, int height) = 0;
        virtual void shutdown() = 0;

        virtual void render() = 0;

        virtual void clearScreen(const PixelColor& color) = 0;

        virtual int getScreenWidth() const = 0;
        virtual int getScreenHeight() const = 0;
        virtual uint32_t getFrameTimer() = 0;
        virtual int getRefreshRate() const = 0;
        virtual float getDeltaTime() const = 0;

        virtual float getUIScale() const { return 1.0f; }

        virtual ImageRenderer* getImageRenderer() = 0;
        virtual GlyphRenderer* getGlyphRenderer() = 0;
};

class ImageRenderer
{
    public:
        virtual ~ImageRenderer() = default;
        virtual void * createTexture(int width, int height) = 0;
        virtual void loadTextureData(void * texture, const uint8_t * rgba, int width, int height) = 0;
        virtual bool canReuseTexture(int allocWidth, int allocHeight, int width, int height) const
        {
            return width <= allocWidth && height <= allocHeight;
        }

        virtual void destroyTexture(void * texture) = 0;
        virtual void drawTexture(void * texture, float xpos, float ypos, uint16_t width, uint16_t height, float degrees, float scaleX, float scaleY, uint8_t alpha) = 0;
        virtual void drawRectangle(float x, float y, float width, float height, PixelColor color) = 0;
        virtual void drawMesh(const MeshVertex* vertices, size_t count) = 0;

        virtual void* createMesh(const MeshVertex* vertices, size_t count) { (void)vertices; (void)count; return nullptr; }
        virtual void destroyMesh(void* mesh) { (void)mesh; }
        virtual void drawMeshInstance(void* mesh, float x, float y, float scaleX, float scaleY) { (void)mesh; (void)x; (void)y; (void)scaleX; (void)scaleY; }
};

class GlyphRenderer {
    public:
        virtual ~GlyphRenderer() = default;

        virtual void* createTexture(uint16_t width, uint16_t height) = 0;
        virtual void loadTextureData(void* texture, FT_Bitmap* bitmap) = 0;
        virtual void destroyTexture(void* texture) = 0;

        virtual void drawQuad(void* texture, int16_t screenX, int16_t screenY, uint16_t width, uint16_t height, const PixelColor& color) = 0;
        virtual void drawFeature(int16_t screenX, int16_t screenY, uint16_t width, uint16_t height, const PixelColor& color) = 0;
};