big refactor: i see i need header files

src/enginePostfx.c

@@ -0,0 +1,36 @@
+#include "engine.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.resolutionLoc = GetShaderLocation(postFX.shader, "resolution");
+    postFX.strengthLoc = GetShaderLocation(postFX.shader, "strength");
+    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);
+}
+
+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);
+}