Post processing and graphics settings for qtFRED

code/def_files/data/effects/fxaa-v.sdr

@@ -8,6 +8,7 @@ void main() {
 }
 #else
 in vec4 vertPosition;
+in vec4 vertTexCoord;
 
 out vec2 v_rcpFrame;
 noperspective out vec2 v_pos;
@@ -20,6 +21,8 @@ layout (std140) uniform genericData {
 void main() {
 	gl_Position = vertPosition;
 	v_rcpFrame = vec2(1.0/rt_w, 1.0/rt_h);
-	v_pos = vertPosition.xy*0.5 + 0.5;
+	// Use the real texcoord rather than deriving it from vertPosition: the draw call may ask for a
+	// sub-rectangle of the source texture, which the clip-space formula ignored. Matches post-v.sdr.
+	v_pos = vertTexCoord.xy;
 }
 #endif

code/graphics/2d.cpp

@@ -859,6 +859,29 @@ bool gr_is_smaa_mode(AntiAliasMode mode) {
 	return mode == AntiAliasMode::SMAA_Low || mode == AntiAliasMode::SMAA_Medium || mode == AntiAliasMode::SMAA_High || mode == AntiAliasMode::SMAA_Ultra;
 }
 
+SCP_vector<float> gr_get_supported_anisotropy_levels()
+{
+	float max;
+	if (!gr_get_property(gr_property::MAX_ANISOTROPY, &max)) {
+		return {};
+	}
+
+	if (max <= 2.0f) {
+		return {};
+	}
+
+	SCP_vector<float> out;
+
+	// We assume here that the anisotropy levels are powers of two...
+	float current = 1.0f;
+	while (current <= max) {
+		out.push_back(current);
+		current *= 2.0f;
+	}
+
+	return out;
+}
+
 static void parse_post_processing_func()
 {
 	bool value;
@@ -1647,6 +1670,13 @@ void gr_screen_resize(int width, int height)
 	gr_screen.save_max_h_unscaled_zoomed = gr_screen.max_h_unscaled_zoomed;
 
 	gr_setup_viewport();
+
+	// The offscreen targets that back the scene/post-processing pipeline were sized for the old
+	// gr_screen; give the backend a chance to grow them before anything renders at the new size.
+	// Backends that already handle this elsewhere (Vulkan, via recreateSwapChain()) leave it unset.
+	if (gr_screen.gf_resize_render_targets) {
+		gr_screen.gf_resize_render_targets();
+	}
 }
 
 void gr_window_to_render_pos(float& x, float& y)

code/graphics/2d.h

@@ -917,6 +917,12 @@ typedef struct screen {
 	std::function<void()> gf_scene_texture_end;
 	std::function<void()> gf_copy_effect_texture;
 
+	// Grow the offscreen render targets that back the scene/post-processing pipeline to cover the
+	// current gr_screen, if they don't already. Called from gr_screen_resize(). Optional: the
+	// Vulkan backend leaves this unset because VulkanRenderer::recreateSwapChain() already owns
+	// resizing its extent-sized targets.
+	std::function<void()> gf_resize_render_targets;
+
 	std::function<void(int zbias)> gf_zbias;
 
 	std::function<void(int)> gf_set_fill_mode;
@@ -1494,6 +1500,12 @@ inline bool gr_get_property(gr_property property, void* destination)
 	return gr_screen.gf_get_property(property, destination);
 }
 
+// Anisotropic filtering levels the current hardware supports: 1.0 (off), then powers of two up to
+// the reported maximum. Empty if anisotropy is unavailable or the hardware caps out below 4x, in
+// which case there is nothing meaningful to offer. Backs both the in-game option's enumerator and
+// qtFRED's Preferences combo, so the two can't drift.
+SCP_vector<float> gr_get_supported_anisotropy_levels();
+
 inline void gr_push_debug_group(const char* name)
 {
 	gr_screen.gf_push_debug_group(name);

code/graphics/opengl/gropengl.cpp

@@ -1126,6 +1126,7 @@ void gr_opengl_init_function_pointers()
 	gr_screen.gf_scene_texture_begin = gr_opengl_scene_texture_begin;
 	gr_screen.gf_scene_texture_end = gr_opengl_scene_texture_end;
 	gr_screen.gf_copy_effect_texture = gr_opengl_copy_effect_texture;
+	gr_screen.gf_resize_render_targets = gr_opengl_resize_render_targets;
 
 	gr_screen.gf_deferred_lighting_begin = gr_opengl_deferred_lighting_begin;
 	gr_screen.gf_deferred_lighting_msaa = gr_opengl_deferred_lighting_msaa;
@@ -1514,7 +1515,7 @@ bool gr_opengl_init(std::unique_ptr<os::GraphicsOperations>&& graphicsOps)
 	opengl_shader_init();
 
 	// post processing effects, after shaders are initialized
-	opengl_setup_scene_textures();
+	opengl_setup_scene_textures(gr_screen.max_w, gr_screen.max_h);
 	opengl_post_process_init();
 
 	// must be called after extensions are setup

code/graphics/opengl/gropengldeferred.cpp

@@ -86,7 +86,7 @@ void gr_opengl_deferred_lighting_begin(bool clearNonColorBufs)
 		Current_shader->program->Uniforms.setTextureUniform("tex", 0);
 		GL_state.SetAlphaBlendMode(gr_alpha_blend::ALPHA_BLEND_NONE);
 		GL_state.SetZbufferType(ZBUFFER_TYPE_NONE);
-		opengl_draw_full_screen_textured(0, 0, 1, 1);
+		opengl_draw_full_screen_scene_texture();
 	} else {
 		// Copy the existing color data into the emissive part of the G-buffer since everything that already existed is
 		// treated as emissive
@@ -159,7 +159,9 @@ void gr_opengl_deferred_lighting_msaa()
 		});
 	GL_state.SetAlphaBlendMode(gr_alpha_blend::ALPHA_BLEND_NONE);
 	GL_state.SetZbufferType(ZBUFFER_TYPE_WRITE);
-	opengl_draw_full_screen_textured(0, 0, 1, 1);
+	// msaa-f.sdr resolves via ivec2(textureSize(texColor) * fragTexCoord), so the texcoords have to
+	// stay inside the rendered sub-rectangle of the multisampled G-buffer.
+	opengl_draw_full_screen_scene_texture();
 }
 
 void gr_opengl_deferred_lighting_end()
@@ -325,8 +327,12 @@ void gr_opengl_deferred_lighting_finish()
 			shadow_cascade_params_bind(offset, count);
 		}
 
-		header->invScreenWidth = 1.0f / gr_screen.max_w;
-		header->invScreenHeight = 1.0f / gr_screen.max_h;
+		// deferred-f.sdr turns gl_FragCoord into a G-buffer texture coordinate with these, so they
+		// have to normalize against the G-buffer's own dimensions. Those only equal gr_screen while
+		// the viewport exactly fills the scene textures -- not after a shrink, and not when the
+		// allocation was clamped by GL_max_renderbuffer_size.
+		header->invScreenWidth = 1.0f / Scene_texture_width;
+		header->invScreenHeight = 1.0f / Scene_texture_height;
 		header->nearPlane = gr_near_plane;
 
 		{
@@ -561,7 +567,8 @@ void gr_opengl_deferred_lighting_finish()
 			data->clip_dist       = Neb2_fog_clip_distance;
 		});
 
-		opengl_draw_full_screen_textured(0.0f, 0.0f, 1.0f, 1.0f);
+		// fog-f.sdr samples the composite and depth targets straight off fragTexCoord.
+		opengl_draw_full_screen_scene_texture();
 
 		if (bDrawNebVolumetrics) {
 			glReadBuffer(GL_COLOR_ATTACHMENT0);
@@ -657,6 +664,12 @@ void gr_opengl_deferred_lighting_finish()
 
 		{
 			GR_DEBUG_SCOPE("Volumetric Nebulae Draw");
+			// Deliberately unscaled. volumetric-f.sdr uses fragTexCoord for two incompatible
+			// things: reconstructing an eye-space ray direction, which needs the full 0..1 range
+			// across the viewport, and sampling composite/depth/emissive, which needs the
+			// rendered sub-rectangle. Scaling here would fix the sampling and skew every ray.
+			// Separating the two needs a second varying (or a scale uniform) in the shader; until
+			// then volumetrics are only correct while the targets exactly match the viewport.
 			opengl_draw_full_screen_textured(0.0f, 0.0f, 1.0f, 1.0f);
 		}
 		GL_state.Texture.Enable(Scene_emissive_texture);