#include "enginePostfx.h"

#include <stddef.h>

PostProcessing CreatePostFX(const char *shaderPath) {
  PostProcessing postFX = {0};
  postFX.shader = LoadShader(NULL, shaderPath);

  if (postFX.shader.id == 0) {
    TraceLog(LOG_ERROR, "Failed to load shader: %s", shaderPath);
    return postFX;
  }

  postFX.strength = 0.0f;
  postFX.time = 0.0f;
  postFX.resolutionLoc = GetShaderLocation(postFX.shader, "resolution");
  postFX.strengthLoc = GetShaderLocation(postFX.shader, "strength");
  postFX.timeLoc = GetShaderLocation(postFX.shader, "time");
  Vector2 resolution = {(float)GetScreenWidth(), (float)GetScreenHeight()};
  SetShaderValue(postFX.shader, postFX.resolutionLoc, &resolution, SHADER_UNIFORM_VEC2);
  return postFX;
}

void UpdatePostFX(PostProcessing *postFX) {
  if (postFX->shader.id == 0)
    return;
  SetShaderValue(postFX->shader, postFX->strengthLoc, &postFX->strength, SHADER_UNIFORM_FLOAT);
  Vector2 resolution = {(float)GetScreenWidth(), (float)GetScreenHeight()};
  SetShaderValue(postFX->shader, postFX->resolutionLoc, &resolution, SHADER_UNIFORM_VEC2);
  if (postFX->timeLoc != -1) {
    postFX->time += GetFrameTime();
    SetShaderValue(postFX->shader, postFX->timeLoc, &postFX->time, SHADER_UNIFORM_FLOAT);
  }
}

void UpdateShaders(PostProcessing *postFX, int count) {
  for (int i = 0; i < count; i++) {
    UpdatePostFX(&postFX[i]);
  }
}

void RenderPostFX(PostProcessing *postFX, RenderTexture2D *target) {
  BeginShaderMode(postFX->shader);
  DrawTextureRec(target->texture, (Rectangle){0, 0, target->texture.width, -target->texture.height},
                 (Vector2){0, 0}, WHITE);
  EndShaderMode();
}

void UnloadPostFX(PostProcessing *postFX) {
  if (postFX->shader.id == 0)
    return;
  UnloadShader(postFX->shader);
}