Fix phosphor shader to work properly for multi-screen games and

multi-window use.

	hlsl/phosphor.fx: Update semantics.

	src/osd/modules/render/d3d/d3dhlsl.cpp: Implement
shaders::delta_time member function.

	src/osd/modules/render/d3d/d3dhlsl.h: Add acc_t and delta_t
members for use by shaders::delta_time.  Member function returns the
amount of time since itself has been called, for use by time-dependent
shaders.

hlsl/phosphor.fx

@@ -94,17 +94,17 @@ VS_OUTPUT vs_main(VS_INPUT Input)
 //-----------------------------------------------------------------------------
 
 uniform float3 Phosphor = float3(0.0f, 0.0f, 0.0f);
-uniform float dt = 0.0f;
-static const float f = 30.0f;
+uniform float DeltaTime = 0.0f;
+static const float F = 30.0f;
 
 float4 ps_main(PS_INPUT Input) : COLOR
 {
 	float4 CurrPix = tex2D(DiffuseSampler, Input.TexCoord);
 	float3 PrevPix = tex2D(PreviousSampler, Input.PrevCoord).rgb;
 
-	PrevPix.r *= Phosphor.r == 0 ? 0 : pow(Phosphor.r, f * dt);
-	PrevPix.g *= Phosphor.g == 0 ? 0 : pow(Phosphor.g, f * dt);
-	PrevPix.b *= Phosphor.b == 0 ? 0 : pow(Phosphor.b, f * dt);
+	PrevPix.r *= Phosphor.r == 0 ? 0 : pow(Phosphor.r, F * DeltaTime);
+	PrevPix.g *= Phosphor.g == 0 ? 0 : pow(Phosphor.g, F * DeltaTime);
+	PrevPix.b *= Phosphor.b == 0 ? 0 : pow(Phosphor.b, F * DeltaTime);
 	float RedMax = max(CurrPix.r, PrevPix.r);
 	float GreenMax = max(CurrPix.g, PrevPix.g);
 	float BlueMax = max(CurrPix.b, PrevPix.b);

src/osd/modules/render/d3d/d3dhlsl.cpp

@@ -164,14 +164,15 @@ private:
 
 shaders::shaders() :
 	d3dintf(nullptr), machine(nullptr), d3d(nullptr), post_fx_enable(false), oversampling_enable(false),
-	num_screens(0), curr_screen(0), shadow_texture(nullptr), options(nullptr), black_surface(nullptr),
-	black_texture(nullptr), recording_movie(false), render_snap(false), snap_copy_target(nullptr),
-	snap_copy_texture(nullptr), snap_target(nullptr), snap_texture(nullptr), snap_width(0), snap_height(0),
-	initialized(false), backbuffer(nullptr), curr_effect(nullptr), default_effect(nullptr),
-	prescale_effect(nullptr), post_effect(nullptr), distortion_effect(nullptr), focus_effect(nullptr),
-	phosphor_effect(nullptr), deconverge_effect(nullptr), color_effect(nullptr), ntsc_effect(nullptr),
-	bloom_effect(nullptr), downsample_effect(nullptr), vector_effect(nullptr), curr_texture(nullptr),
-	curr_render_target(nullptr), curr_poly(nullptr), d3dx_create_effect_from_file_ptr(nullptr)
+	num_screens(0), curr_screen(0), acc_t(0), delta_t(0), shadow_texture(nullptr), options(nullptr),
+	black_surface(nullptr), black_texture(nullptr), recording_movie(false), render_snap(false),
+	snap_copy_target(nullptr), snap_copy_texture(nullptr), snap_target(nullptr), snap_texture(nullptr),
+	snap_width(0), snap_height(0), initialized(false), backbuffer(nullptr), curr_effect(nullptr),
+	default_effect(nullptr), prescale_effect(nullptr), post_effect(nullptr), distortion_effect(nullptr),
+	focus_effect(nullptr), phosphor_effect(nullptr), deconverge_effect(nullptr), color_effect(nullptr),
+	ntsc_effect(nullptr), bloom_effect(nullptr), downsample_effect(nullptr), vector_effect(nullptr),
+	curr_texture(nullptr), curr_render_target(nullptr), curr_poly(nullptr),
+	d3dx_create_effect_from_file_ptr(nullptr)
 {
 }
 
@@ -900,6 +901,18 @@ void shaders::blit(
 	curr_effect->end();
 }
 
+double shaders::delta_time()
+{
+	double t;
+
+	if (curr_screen == 0) {
+		t = machine->time().as_double();
+		delta_t = t - acc_t;
+		acc_t = t;
+	}
+	return delta_t;
+}
+
 
 //============================================================
 //  shaders::find_render_target
@@ -1061,11 +1074,7 @@ int shaders::defocus_pass(d3d_render_target *rt, int source_index, poly_info *po
 
 int shaders::phosphor_pass(d3d_render_target *rt, int source_index, poly_info *poly, int vertnum)
 {
-	static double ct = 0;
-
 	int next_index = source_index;
-	float dt;
-	double t;
 
 	// skip phosphor if no influencing settings
 	if (options->phosphor[0] == 0.0f && options->phosphor[1] == 0.0f && options->phosphor[2] == 0.0f)
@@ -1074,15 +1083,12 @@ int shaders::phosphor_pass(d3d_render_target *rt, int source_index, poly_info *p
 	}
 
 	// Shader needs time between last update
-	t = machine->time().as_double();
-	dt = (float) (t - ct);
-	ct = t;
 	curr_effect = phosphor_effect;
 	curr_effect->update_uniforms();
 	curr_effect->set_texture("Diffuse", rt->target_texture[next_index]);
 	curr_effect->set_texture("LastPass", rt->cache_texture);
 	curr_effect->set_bool("Passthrough", false);
-	curr_effect->set_float("dt", dt);
+	curr_effect->set_float("DeltaTime", delta_time());
 
 	next_index = rt->next_index(next_index);
 	blit(rt->target_surface[next_index], false, D3DPT_TRIANGLELIST, 0, 2);

src/osd/modules/render/d3d/d3dhlsl.h

@@ -319,7 +319,7 @@ private:
 	void                    enumerate_screens();
 
 	void                    render_snapshot(IDirect3DSurface9 *surface);
-
+	double                  delta_time();  // Time since last call to itself; only updates for Screen 0
 	d3d_render_target*      find_render_target(int source_width, int source_height, uint32_t screen_index);
 
 	rgb_t                   apply_color_convolution(rgb_t color);
@@ -349,6 +349,8 @@ private:
 	bool                    oversampling_enable;        // oversampling enable flag
 	int                     num_screens;                // number of emulated physical screens
 	int                     curr_screen;                // current screen for render target operations
+	double                  acc_t;                      // accumulated machine time
+	double                  delta_t;                    // time since last call to delta_time
 	bitmap_argb32           shadow_bitmap;              // shadow mask bitmap for post-processing shader
 	texture_info *          shadow_texture;             // shadow mask texture for post-processing shader
 	hlsl_options *          options;                    // current options