From 1e0ea56efc5cd55579ca5f2b2cccb49e0100b143 Mon Sep 17 00:00:00 2001
From: Bastien Bouclet <bastien.bouclet@gmail.com>
Date: Thu, 19 Jan 2012 21:04:01 +0100
Subject: [PATCH] MYST3: Implement the blur effect for J'nanin's projectors.

---
 engines/myst3/movie.cpp | 50 ++++++++++++++++++++++++++++++++++++-----
 engines/myst3/movie.h   |  4 ++++
 2 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/engines/myst3/movie.cpp b/engines/myst3/movie.cpp
index e6b324c62da..db3bdabf100 100644
--- a/engines/myst3/movie.cpp
+++ b/engines/myst3/movie.cpp
@@ -301,6 +301,11 @@ ProjectorMovie::ProjectorMovie(Myst3Engine *vm, uint16 id, Graphics::Surface *ba
 	_background(background),
 	_frame(0) {
 	_enabled = true;
+
+	for (uint i = 0; i < kBlurIterations; i++) {
+		_blurTableX[i] = sin(2 * M_PI * i / (float) kBlurIterations) * 256.0;
+		_blurTableY[i] = cos(2 * M_PI * i / (float) kBlurIterations) * 256.0;
+	}
 }
 
 ProjectorMovie::~ProjectorMovie() {
@@ -323,22 +328,57 @@ void ProjectorMovie::update() {
 		_frame->copyFrom(*frame);
 	}
 
+	uint16 focus = _vm->_state->getProjectorBlur() / 10;
 	uint16 zoom = _vm->_state->getProjectorZoom();
 	uint16 backgroundX = (_vm->_state->getProjectorX() - zoom / 2) / 10;
 	uint16 backgroundY = (_vm->_state->getProjectorY() - zoom / 2) / 10;
 	float delta = zoom / 10.0 / _frame->w;
 
+	// For each pixel in the target image
 	for (uint i = 0; i < _frame->h; i++) {
 		uint32 *dst = (uint32 *)_frame->getBasePtr(0, i);
 		for (uint j = 0; j < _frame->w; j++) {
-			uint8 a, r, g, b;
-			uint32 *src = (uint32 *)_background->getBasePtr(backgroundX + j * delta, backgroundY + i * delta);
+			uint8 a, depth;
+			uint16 r = 0, g = 0, b = 0;
+			uint32 srcX = backgroundX + j * delta;
+			uint32 srcY = backgroundY + i * delta;
+			uint32 *src = (uint32 *)_background->getBasePtr(srcX, srcY);
 
 			// Keep the alpha channel from the previous frame
-			Graphics::colorToARGB< Graphics::ColorMasks<8888> >(*dst, a, r, g, b);
+			a = *dst >> 24;
 
-			// Get the colors from the background
-			Graphics::colorToRGB< Graphics::ColorMasks<8888> >(*src, r, g, b);
+			// Get the depth from the background
+			depth = *src >> 24;
+
+			// Compute the blur level from the focus point and the depth of the current point
+			uint8 blurLevel = abs(focus - depth) + 1;
+			
+			// No need to compute the effect for transparent pixels
+			if (a != 0) {
+				// The blur effect is done by mixing the color components from the pixel at (srcX, srcY)
+				// and other pixels on the same row / column
+				uint cnt = 0;
+				for (uint k = 0; k < kBlurIterations; k++) {
+					uint8 blurR, blurG, blurB;
+					uint32 blurX = srcX + ((uint32) (blurLevel * _blurTableX[k] * delta) >> 12); // >> 12 = / 256 / 16
+					uint32 blurY = srcY + ((uint32) (blurLevel * _blurTableY[k] * delta) >> 12);
+
+					if (blurX >= 0 && blurX < 1024 && blurY >= 0 && blurY < 1024) {
+						uint32 *blur = (uint32 *)_background->getBasePtr(blurX, blurY);
+
+						Graphics::colorToRGB< Graphics::ColorMasks<8888> >(*blur, blurR, blurG, blurB);
+						r += blurR;
+						g += blurG;
+						b += blurB;
+						cnt++;
+					}
+				}
+
+				// Divide the components by the number of pixels used in the blur effect
+				r /= cnt;
+				g /= cnt;
+				b /= cnt;
+			}
 
 			// Draw the new frame
 			*dst++ = Graphics::ARGBToColor< Graphics::ColorMasks<8888> >(a, r, g, b);
diff --git a/engines/myst3/movie.h b/engines/myst3/movie.h
index 9d78eedcdd6..ce810ee5dfc 100644
--- a/engines/myst3/movie.h
+++ b/engines/myst3/movie.h
@@ -141,6 +141,10 @@ public:
 private:
 	Graphics::Surface *_background;
 	Graphics::Surface *_frame;
+
+	static const uint kBlurIterations = 30;
+	uint8 _blurTableX[kBlurIterations];
+	uint8 _blurTableY[kBlurIterations];
 };
 
 } /* namespace Myst3 */