gl: when loading custom textures, don't delete regular textures until after the current frame

regular textures might be referenced by the current frame and deleting them cause gl errors
Issue #144

core/rend/gl4/gles.cpp

@@ -611,7 +611,6 @@ static void resize(int w, int h)
 
 static bool RenderFrame()
 {
-	DoCleanup();
 	create_modvol_shader();
 
 	const bool is_rtt = pvrrc.isRTT;

core/rend/gles/gles.cpp

@@ -1040,6 +1040,7 @@ bool ProcessFrame(TA_context* ctx)
 {
 	if (KillTex)
 		TexCache.Clear();
+	TexCache.Cleanup();
 
 	if (ctx->rend.isRenderFramebuffer)
 	{
@@ -1050,7 +1051,6 @@ bool ProcessFrame(TA_context* ctx)
 		if (!ta_parse_vdrc(ctx))
 			return false;
 	}
-	TexCache.CollectCleanup();
 
 	return true;
 }
@@ -1075,7 +1075,6 @@ static void upload_vertex_indices()
 
 bool RenderFrame()
 {
-	DoCleanup();
 	create_modvol_shader();
 
 	bool is_rtt = pvrrc.isRTT;

core/rend/gles/gles.h

@@ -143,7 +143,6 @@ void SetupMatrices(float dc_width, float dc_height,
 				   float &ds2s_offs_x, glm::mat4& normal_mat, glm::mat4& scissor_mat);
 
 text_info raw_GetTexture(TSP tsp, TCW tcw);
-void DoCleanup();
 void SetCull(u32 CullMode);
 s32 SetTileClip(u32 val, GLint uniform);
 void SetMVS_Mode(ModifierVolumeMode mv_mode, ISP_Modvol ispc);
@@ -228,6 +227,20 @@ public:
 
 class TextureCache final : public BaseTextureCache<TextureCacheData>
 {
+public:
+	void Cleanup()
+	{
+		if (!texturesToDelete.empty())
+		{
+			glcache.DeleteTextures((GLsizei)texturesToDelete.size(), &texturesToDelete[0]);
+			texturesToDelete.clear();
+		}
+		CollectCleanup();
+	}
+	void DeleteLater(GLuint texId) { texturesToDelete.push_back(texId); }
+
+private:
+	std::vector<GLuint> texturesToDelete;
 };
 extern TextureCache TexCache;
 

core/rend/gles/gltex.cpp

@@ -321,7 +321,7 @@ u64 gl_GetTexture(TSP tsp, TCW tcw)
 	{
 		if (tf->IsCustomTextureAvailable())
 		{
-			glcache.DeleteTextures(1, &tf->texID);
+			TexCache.DeleteLater(tf->texID);
 			tf->texID = glcache.GenTexture();
 			tf->CheckCustomTexture();
 		}
@@ -340,10 +340,6 @@ u64 gl_GetTexture(TSP tsp, TCW tcw)
 	return tf->texID;
 }
 
-void DoCleanup()
-{
-}
-
 GLuint fbTextureId;
 
 void RenderFramebuffer()