[Scummvm-git-logs] scummvm master -> df2eb82b83fbeac3ae38d6f7627200ae51382658

[sev-]

This automated email contains information about 1 new commit which have been
pushed to the 'scummvm' repo located at https://github.com/scummvm/scummvm .

Summary:
df2eb82b83 VIDEO: QTVR: Added comments to hotspot computations


Commit: df2eb82b83fbeac3ae38d6f7627200ae51382658
    https://github.com/scummvm/scummvm/commit/df2eb82b83fbeac3ae38d6f7627200ae51382658
Author: Eugene Sandulenko (sev at scummvm.org)
Date: 2025-02-10T00:31:56+01:00

Commit Message:
VIDEO: QTVR: Added comments to hotspot computations

Changed paths:
    video/qtvr_decoder.cpp


diff --git a/video/qtvr_decoder.cpp b/video/qtvr_decoder.cpp
index 3ddda3eadf9..8a0031be6c3 100644
--- a/video/qtvr_decoder.cpp
+++ b/video/qtvr_decoder.cpp
@@ -473,17 +473,28 @@ int QuickTimeDecoder::PanoTrackHandler::lookupHotspot(int16 mx, int16 my) {
 	float minTiltY = tan(desc->_vPanBottom * M_PI / 180.0f);
 	float maxTiltY = tan(desc->_vPanTop * M_PI / 180.0f);
 
-	mousePixelVector[0] = topRightVector[0] * ((float)(mx - w / 2) / (float)w * 2.0);
+	// Compute the side edge vector by interpolating between topRightVector and
+	// bottomRightVector based on the mouse Y position
+	mousePixelVector[0] = topRightVector[0];
 	mousePixelVector[1] = topRightVector[1] + ((float)(my - h / 2) / (float)h * (topRightVector[1] - bottomRightVector[1]));
 	mousePixelVector[2] = topRightVector[2];
 
+	// Multiply the X value ([0]) of the result of that on a value ranging from -1 to 1
+	// based on the mouse X position to get the mouse pixel vector
+	mousePixelVector[0] = mousePixelVector[0] * ((float)(mx - w / 2) / (float)w * 2.0);
+
+	// The yaw angle is atan2(mousePixelVector[0], mousePixelVector[2]), multiply that
+	// by the panorama width and divide by 2*pi to get the horizontal coordinate
 	float yawAngle = atan2(mousePixelVector[0], mousePixelVector[2]);
 
 	// panorama is turned 90 degrees, width is height
 	int hotX = yawAngle * (float)_constructedPano->h / 2.0 / M_PI;
 
+	// To get the vertical coordinate, need to project the vector on to a unit cylinder.
+	// To do that, compute the length of the XZ vector,
 	float xzVectorLen = sqrt(mousePixelVector[0] * mousePixelVector[0] + mousePixelVector[2] * mousePixelVector[2]);
 
+	// then compute projectedY = mousePixelVector[1] / xzVectorLen
 	int hotY = (int)((float)mousePixelVector[1] / (float)xzVectorLen * (float)_constructedPano->w);
 
 	warning("x: %d y: %d (min: %f max: %f) m: [%f, %f, %f] vectorLen: %f", hotX, hotY, minTiltY, maxTiltY, mousePixelVector[0], mousePixelVector[1], mousePixelVector[2], xzVectorLen);