Hardware mode y-shearing matches software mode mouselook

src/doomdef.h

@@ -415,6 +415,9 @@ extern INT32 cv_debug;
 extern UINT8 shiftdown, ctrldown, altdown;
 extern boolean capslock;
 
+// WARNING: a should be unsigned but to add with 2048, it isn't!
+#define AIMINGTODY(a) (FINETANGENT((2048+(((INT32)a)>>ANGLETOFINESHIFT)) & FINEMASK)*160)
+
 // if we ever make our alloc stuff...
 #define ZZ_Alloc(x) Z_Malloc(x, PU_STATIC, NULL)
 

src/hardware/hw_defs.h

@@ -158,6 +158,7 @@ typedef struct
 	boolean     mirror;          // SRB2Kart: Encore Mode
 #endif
 	boolean     shearing;        // 14042019
+	angle_t     viewaiming;      // 17052019
 } FTransform;
 
 // Transformed vector, as passed to HWR API

src/hardware/hw_drv.h

@@ -48,7 +48,7 @@ EXPORT void HWRAPI(SetSpecialState) (hwdspecialstate_t IdState, INT32 Value);
 //Hurdler: added for new development
 EXPORT void HWRAPI(DrawModel) (model_t *model, INT32 frameIndex, INT32 duration, INT32 tics, INT32 nextFrameIndex, FTransform *pos, float scale, UINT8 flipped, FSurfaceInfo *Surface);
 EXPORT void HWRAPI(CreateModelVBOs) (model_t *model);
-EXPORT void HWRAPI(SetTransform) (FTransform *ptransform, angle_t viewaiming);
+EXPORT void HWRAPI(SetTransform) (FTransform *stransform);
 EXPORT INT32 HWRAPI(GetTextureUsed) (void);
 
 EXPORT void HWRAPI(FlushScreenTextures) (void);

src/hardware/hw_main.c

@@ -3938,7 +3938,7 @@ void HWR_RenderDrawNodes(void)
 	} // loop++
 
 	// Okay! Let's draw it all! Woo!
-	HWD.pfnSetTransform(&atransform, aimingangle);
+	HWD.pfnSetTransform(&atransform);
 	HWD.pfnSetShader(0);
 
 	for (i = 0; i < p; i++)
@@ -4459,6 +4459,15 @@ void HWR_DrawSkyBackground(void)
 
 	angleturn = (((float)ANGLE_45-1.0f)*aspectratio)*dimensionmultiply;
 
+	if (cv_grshearing.value)
+	{
+		// Doesn't really make sense, but what can I do?
+		angle_t dy = FixedAngle(FixedMul(360*FRACUNIT, FixedDiv(AIMINGTODY(aimingangle), 900*FRACUNIT)));
+		v[3].t = v[2].t -= ((float) dy / angleturn);
+		v[0].t = v[1].t -= ((float) dy / angleturn);
+	}
+	else
+	{
 		if (angle > ANGLE_180) // Do this because we don't want the sky to suddenly teleport when crossing over 0 to 360 and vice versa
 		{
 			angle = InvAngle(angle);
@@ -4470,6 +4479,7 @@ void HWR_DrawSkyBackground(void)
 			v[3].t = v[2].t -= ((float) angle / angleturn);
 			v[0].t = v[1].t -= ((float) angle / angleturn);
 		}
+	}
 
 	HWD.pfnSetShader(7);	// sky shader
 	HWD.pfnDrawPolygon(NULL, v, 4, 0);
@@ -4560,12 +4570,11 @@ void HWR_RenderFrame(INT32 viewnumber, player_t *player, boolean skybox)
 	atransform.scalez = 1;
 
 	// 14042019
-	if (!cv_grshearing.value)
-	{
 	gr_aimingangle = aimingangle;
 	atransform.shearing = false;
-	}
-	else
+	atransform.viewaiming = aimingangle;
+
+	if (cv_grshearing.value)
 	{
 		gr_aimingangle = 0;
 		atransform.shearing = true;
@@ -4609,14 +4618,14 @@ void HWR_RenderFrame(INT32 viewnumber, player_t *player, boolean skybox)
 	gld_FrustrumSetup();
 #endif
 
-	// Set transform and shader
-	HWD.pfnSetTransform(&atransform, aimingangle);
+	// Set transform.
+	HWD.pfnSetTransform(&atransform);
+
+	// Reset the shader state.
+	HWD.pfnSetSpecialState(HWD_SET_SHADERS, cv_grshaders.value);
 	HWD.pfnSetShader(0);
 
-	// Check for shaders
-	HWD.pfnSetSpecialState(HWD_SET_SHADERS, cv_grshaders.value);
-
-	// Check for fog (shader)
+	// Check if fog is enabled.
 	if (cv_grfog.value)
 		HWR_FoggingOn(); // First of all, turn it on, set the default user settings too
 	else
@@ -4639,7 +4648,7 @@ void HWR_RenderFrame(INT32 viewnumber, player_t *player, boolean skybox)
 		HWR_RenderDrawNodes();
 
 	// Unset transform and shader
-	HWD.pfnSetTransform(NULL, 0.0f);
+	HWD.pfnSetTransform(NULL);
 	HWD.pfnUnSetShader();
 
 	// Disable fog

src/hardware/r_opengl/r_opengl.c

@@ -2186,7 +2186,7 @@ EXPORT void HWRAPI(DrawModel) (model_t *model, INT32 frameIndex, INT32 duration,
 // -----------------+
 // SetTransform     :
 // -----------------+
-EXPORT void HWRAPI(SetTransform) (FTransform *stransform, angle_t viewaiming)
+EXPORT void HWRAPI(SetTransform) (FTransform *stransform)
 {
 	static boolean special_splitscreen;
 	GLdouble used_fov;
@@ -2232,12 +2232,8 @@ EXPORT void HWRAPI(SetTransform) (FTransform *stransform, angle_t viewaiming)
 	// https://zdoom.org/wiki/Y-shearing
 	if (shearing)
 	{
-		float tilt = (float)(viewaiming>>ANGLETOFINESHIFT)*(360.0f/(float)FINEANGLES);
-		if (tilt >= 270.0f)
-			tilt = -(90.0f - (tilt - 270.0f));
-		tilt /= 24.0f;		// ?????????
-
-		pglTranslatef(0.0f, -tilt, 0.0f);
+		float dy = FIXED_TO_FLOAT(AIMINGTODY(stransform->viewaiming)) * 2; //screen_width/BASEVIDWIDTH;
+		pglTranslatef(0.0f, -dy/BASEVIDHEIGHT, 0.0f);
 	}
 
 	if (special_splitscreen)

src/r_main.c

@@ -738,29 +738,31 @@ subsector_t *R_IsPointInSubsector(fixed_t x, fixed_t y)
 
 static mobj_t *viewmobj;
 
-// WARNING: a should be unsigned but to add with 2048, it isn't!
-#define AIMINGTODY(a) ((FINETANGENT((2048+(((INT32)a)>>ANGLETOFINESHIFT)) & FINEMASK)*160)>>FRACBITS)
-
 // recalc necessary stuff for mouseaiming
 // slopes are already calculated for the full possible view (which is 4*viewheight).
 // 18/08/18: (No it's actually 16*viewheight, thanks Jimita for finding this out)
 static void R_SetupFreelook(void)
 {
 	INT32 dy = 0;
-	if (rendermode == render_soft)
-	{
+
 	// clip it in the case we are looking a hardware 90 degrees full aiming
 	// (lmps, network and use F12...)
+	if (rendermode == render_soft
+#ifdef HWRENDER
+		|| cv_grshearing.value
+#endif
+	)
 		G_SoftwareClipAimingPitch((INT32 *)&aimingangle);
-		dy = AIMINGTODY(aimingangle) * viewwidth/BASEVIDWIDTH;
+
+	if (rendermode == render_soft)
+	{
+		dy = (AIMINGTODY(aimingangle)>>FRACBITS) * viewwidth/BASEVIDWIDTH;
 		yslope = &yslopetab[viewheight*8 - (viewheight/2 + dy)];
 	}
 	centery = (viewheight/2) + dy;
 	centeryfrac = centery<<FRACBITS;
 }
 
-#undef AIMINGTODY
-
 void R_SetupFrame(player_t *player, boolean skybox)
 {
 	camera_t *thiscam;