paint: expose gamma and contrast

paint/shaders/compositor_pass.kong

@@ -5,6 +5,8 @@ const constants: {
 	grain_strength: float;
 	tonemap_strength: float; // 0.0 or 1.0
 	lut_size: float;
+	contrast_strength: float;
+	gamma_strength: float;
 };
 
 #[set(everything)]
@@ -84,6 +86,13 @@ fun compositor_pass_frag(input: vert_out): float4 {
 		color.rgb = lerp3(color.rgb, tonemap_filmic(color.rgb), constants.tonemap_strength);
 	}
 
+	// Contrast
+	color.rgb = (color.rgb - float3(0.5, 0.5, 0.5)) * constants.contrast_strength + float3(0.5, 0.5, 0.5);
+
+	// Gamma
+	var inv_gamma: float = 1.0 / max(constants.gamma_strength, 0.01);
+	color.rgb = pow3(max3(color.rgb, float3(0.0, 0.0, 0.0)), float3(inv_gamma, inv_gamma, inv_gamma));
+
 	return color;
 }
 

paint/sources/config.c

@@ -75,6 +75,8 @@ void config_save() {
 	json_encode_f32("rp_bloom", g_config->rp_bloom);
 	json_encode_f32("rp_vignette", g_config->rp_vignette);
 	json_encode_f32("rp_grain", g_config->rp_grain);
+	json_encode_f32("rp_contrast", g_config->rp_contrast);
+	json_encode_f32("rp_gamma", g_config->rp_gamma);
 	json_encode_string("lut_path", g_config->lut_path);
 	json_encode_bool("texture_filter", g_config->texture_filter);
 	json_encode_string_array("recent_projects", g_config->recent_projects);
@@ -180,6 +182,8 @@ void config_init() {
 		g_config->rp_bloom         = 0.0;
 		g_config->rp_vignette      = 0.2;
 		g_config->rp_grain         = 0.09;
+		g_config->rp_contrast      = 1.0;
+		g_config->rp_gamma         = 1.0;
 		g_config->lut_path         = "";
 		g_config->texture_filter   = true;
 #if defined(IRON_ANDROID) || defined(IRON_IOS)

paint/sources/startup.c

@@ -3082,7 +3082,7 @@ scene_t *startup_get_scene(void) {
 				ve->data                       = "float2";
 				sc->vertex_elements->buffer[0] = ve;
 			}
-			sc->constants = (shader_const_t_array_t *)any_array_create(4);
+			sc->constants = (shader_const_t_array_t *)any_array_create(6);
 			{
 				shader_const_t *c        = (shader_const_t *)gc_alloc(sizeof(shader_const_t));
 				c->name                  = "vignette_strength";
@@ -3111,6 +3111,20 @@ scene_t *startup_get_scene(void) {
 				c->link                  = "_lut_size";
 				sc->constants->buffer[3] = c;
 			}
+			{
+				shader_const_t *c        = (shader_const_t *)gc_alloc(sizeof(shader_const_t));
+				c->name                  = "contrast_strength";
+				c->type                  = "float";
+				c->link                  = "_contrast_strength";
+				sc->constants->buffer[4] = c;
+			}
+			{
+				shader_const_t *c        = (shader_const_t *)gc_alloc(sizeof(shader_const_t));
+				c->name                  = "gamma_strength";
+				c->type                  = "float";
+				c->link                  = "_gamma_strength";
+				sc->constants->buffer[5] = c;
+			}
 			sc->texture_units = (tex_unit_t_array_t *)any_array_create(2);
 			{
 				tex_unit_t *tu               = (tex_unit_t *)gc_alloc(sizeof(tex_unit_t));

paint/sources/types.h

@@ -96,6 +96,8 @@ typedef struct config {
 	f32   rp_bloom;
 	f32   rp_vignette;
 	f32   rp_grain;
+	f32   rp_contrast;
+	f32   rp_gamma;
 	char *lut_path; // .cube
 	bool  texture_filter;
 	// Application

paint/sources/ui/box_preferences.c

@@ -670,6 +670,20 @@ void box_preferences_viewport_tab() {
 		}
 	}
 
+	ui_handle_t *h_contrast = ui_handle(__ID__);
+	h_contrast->f           = g_config->rp_contrast;
+	g_config->rp_contrast   = ui_slider(h_contrast, tr("Contrast"), 0.0, 2.0, true, 100.0, true, UI_ALIGN_RIGHT, true);
+	if (h_contrast->changed) {
+		g_context->ddirty = 2;
+	}
+
+	ui_handle_t *h_gamma = ui_handle(__ID__);
+	h_gamma->f           = g_config->rp_gamma;
+	g_config->rp_gamma   = ui_slider(h_gamma, tr("Gamma"), 0.0, 2.0, true, 100.0, true, UI_ALIGN_RIGHT, true);
+	if (h_gamma->changed) {
+		g_context->ddirty = 2;
+	}
+
 	ui_handle_t *h_vignette = ui_handle(__ID__);
 	h_vignette->f           = g_config->rp_vignette;
 	g_config->rp_vignette   = ui_slider(h_vignette, tr("Vignette"), 0.0, 1.0, true, 100.0, true, UI_ALIGN_RIGHT, true);

paint/sources/uniforms.c

@@ -42,6 +42,12 @@ f32 uniforms_ext_f32_link(object_t *object, material_data_t *mat, char *link) {
 	else if (string_equals(link, "_grain_strength")) {
 		return g_config->rp_grain;
 	}
+	else if (string_equals(link, "_contrast_strength")) {
+		return g_config->rp_contrast;
+	}
+	else if (string_equals(link, "_gamma_strength")) {
+		return g_config->rp_gamma;
+	}
 	else if (string_equals(link, "_tonemap_strength")) {
 		bool tonemap = g_context->viewport_mode == VIEWPORT_MODE_LIT || g_context->viewport_mode == VIEWPORT_MODE_PATH_TRACE;
 		return tonemap ? 1.0 : 0.0;