Implement 1-Texture ADD & SUB for image tint

Makes the texture use 1-RGB mode instead of RGB mode for ADD and SUB if the tint function is called with `C2D_TintOneMinusAdd` or `C2D_TintOneMinusSub`

Author: KirbysDarkNebula

include/c2d/base.h

@@ -39,6 +39,8 @@ typedef enum
 	C2D_TintLuma,  ///< Tint color multiplied by grayscale converted texture color
 	C2D_TintAdd,  ///< Tint color added to the texture color
 	C2D_TintSub,  ///< Tint color subtracted from the texture color
+	C2D_TintOneMinusAdd,  ///< 1 - Texture.rgb + tint color
+	C2D_TintOneMinusSub,  ///< 1 - Texture.rgb - tint color 
 } C2D_TintMode;
 
 typedef struct

source/base.c

@@ -335,6 +335,12 @@ bool C2D_SetTintMode(C2D_TintMode mode)
 		case C2D_TintSub:
 			new_mode = C2DiF_Mode_ImageSub;
 			break;
+		case C2D_TintOneMinusAdd:
+			new_mode = C2DiF_Mode_ImageOMAdd;
+			break;
+		case C2D_TintOneMinusSub:
+			new_mode = C2DiF_Mode_ImageOMSub;
+			break;
 	}
 
 	ctx->flags = (ctx->flags &~ C2DiF_TintMode_Mask) | (new_mode << (C2DiF_TintMode_Shift - C2DiF_Mode_Shift));
@@ -721,21 +727,26 @@ void C2Di_Update(void)
 			break;
 		}
 		case C2DiF_Mode_ImageAdd:
+		case C2DiF_Mode_ImageOMAdd:
 		{
 			// Use texenv to blend the color source with the addition-tinted version of it,
 			// according to a parameter that is passed through with the help of proctex.
 			proctex = C2DiF_ProcTex_Blend;
 
 			// texenv0 = texclr + vtxcolor
+			// texenv0 = (1-texclr) + vtxcolor
 			env = C3D_GetTexEnv(0);
 			C3D_TexEnvInit(env);
-			C3D_TexEnvSrc(env, C3D_Both, GPU_TEXTURE0, GPU_PRIMARY_COLOR, GPU_PRIMARY_COLOR);
+			C3D_TexEnvSrc(env, C3D_RGB, GPU_TEXTURE0, GPU_PRIMARY_COLOR, GPU_PRIMARY_COLOR);
+			if (mode == C2DiF_Mode_ImageOMAdd){ // if OM set to ONE MINUS
+				C3D_TexEnvOpRgb(env, GPU_TEVOP_RGB_ONE_MINUS_SRC_COLOR, GPU_TEVOP_RGB_SRC_COLOR, GPU_TEVOP_RGB_ONE_MINUS_SRC_ALPHA);
+			}
 			C3D_TexEnvFunc(env, C3D_RGB, GPU_ADD);
 
 			// texenv1.rgb = mix(texclr.rgb, texenv0.rgb, vtx.blend.y);
 			env = C3D_GetTexEnv(1);
 			C3D_TexEnvInit(env);
-			C3D_TexEnvSrc(env, C3D_RGB, GPU_TEXTURE0, GPU_PREVIOUS, GPU_TEXTURE3);
+			C3D_TexEnvSrc(env, C3D_Both, GPU_TEXTURE0, GPU_PREVIOUS, GPU_TEXTURE3);
 			C3D_TexEnvOpRgb(env, GPU_TEVOP_RGB_SRC_COLOR, GPU_TEVOP_RGB_SRC_COLOR, GPU_TEVOP_RGB_ONE_MINUS_SRC_ALPHA);
 			C3D_TexEnvFunc(env, C3D_RGB, GPU_INTERPOLATE);
 
@@ -745,21 +756,26 @@ void C2Di_Update(void)
 			break;
 		}
 		case C2DiF_Mode_ImageSub:
+		case C2DiF_Mode_ImageOMSub:
 		{
 			// Use texenv to blend the color source with the subtraction-tinted version of it,
 			// according to a parameter that is passed through with the help of proctex.
 			proctex = C2DiF_ProcTex_Blend;
 
 			// texenv0 = texclr - vtxcolor
+			// texenv0 = (1-texclr) - vtxcolor
 			env = C3D_GetTexEnv(0);
 			C3D_TexEnvInit(env);
-			C3D_TexEnvSrc(env, C3D_Both, GPU_TEXTURE0, GPU_PRIMARY_COLOR, GPU_PRIMARY_COLOR);
+			C3D_TexEnvSrc(env, C3D_RGB, GPU_TEXTURE0, GPU_PRIMARY_COLOR, GPU_PRIMARY_COLOR);
+			if (mode == C2DiF_Mode_ImageOMSub){ // if OM set to ONE MINUS
+				C3D_TexEnvOpRgb(env, GPU_TEVOP_RGB_ONE_MINUS_SRC_COLOR, GPU_TEVOP_RGB_SRC_COLOR, GPU_TEVOP_RGB_ONE_MINUS_SRC_ALPHA);
+			}
 			C3D_TexEnvFunc(env, C3D_RGB, GPU_SUBTRACT);
 
 			// texenv1.rgb = mix(texclr.rgb, texenv0.rgb, vtx.blend.y);
 			env = C3D_GetTexEnv(1);
 			C3D_TexEnvInit(env);
-			C3D_TexEnvSrc(env, C3D_RGB, GPU_TEXTURE0, GPU_PREVIOUS, GPU_TEXTURE3);
+			C3D_TexEnvSrc(env, C3D_Both, GPU_TEXTURE0, GPU_PREVIOUS, GPU_TEXTURE3);
 			C3D_TexEnvOpRgb(env, GPU_TEVOP_RGB_SRC_COLOR, GPU_TEVOP_RGB_SRC_COLOR, GPU_TEVOP_RGB_ONE_MINUS_SRC_ALPHA);
 			C3D_TexEnvFunc(env, C3D_RGB, GPU_INTERPOLATE);
 

source/internal.h

@@ -57,6 +57,8 @@ enum
 	C2DiF_Mode_ImageLuma  = 5   << C2DiF_Mode_Shift,
 	C2DiF_Mode_ImageAdd   = 6   << C2DiF_Mode_Shift,
 	C2DiF_Mode_ImageSub   = 7   << C2DiF_Mode_Shift,
+	C2DiF_Mode_ImageOMAdd = 8   << C2DiF_Mode_Shift,
+	C2DiF_Mode_ImageOMSub = 9   << C2DiF_Mode_Shift,
 
 	C2DiF_ProcTex_Shift  = 12,
 	C2DiF_ProcTex_Mask   = 0xf << C2DiF_ProcTex_Shift,