spotlight example, each spot has own radius, mouse countrol (#1148)

NB glsl100 shader needs testing on "bare metal"

Co-authored-by: codifies <[email protected]>

2 files changed, 78 insertions, 36 deletions

diff --git a/examples/shaders/resources/shaders/glsl100/spotlight.fs b/examples/shaders/resources/shaders/glsl100/spotlight.fs
index 204b89a7..65612753 100644
--- a/examples/shaders/resources/shaders/glsl100/spotlight.fs
+++ b/examples/shaders/resources/shaders/glsl100/spotlight.fs
@@ -2,50 +2,67 @@
 
 precision mediump float;
 
-#define     MAX_SPOTS			4
-#define		RADIUS				256.0
-#define		INNER				200.0
+#define     MAX_SPOTS			3
 
-// Inputs
-// array of spotlight positions
-uniform vec2 spots[MAX_SPOTS];
 
-uniform float screenWidth; // width of the screen
+struct Spot {
+    vec2 pos;		// window coords of spot
+    float inner;	// inner fully transparent centre radius
+    float radius;	// alpha fades out to this radius
+};
+
+uniform Spot spots[MAX_SPOTS];      // Spotlight positions array
+uniform float screenWidth; // Width of the screen
 
 void main()
 {
 
-	float alpha;
+	float alpha = 1.0;
 	// get the position of the current fragment (screen coordinates!)
 	vec2 pos = vec2(gl_FragCoord.x, gl_FragCoord.y);
 
 	
 	// find out which spotlight is nearest
 	float d = 65000.0; // some high value
-	float di = 0.0;
+	int fi = -1;
 
     for (int i = 0; i < MAX_SPOTS; i++)
     {
-		di = distance(pos, spots[i]);
-		if (d > di) d = di;
+		for (int j = 0; j < MAX_SPOTS; j++)
+		{
+			float dj = distance(pos, spots[j].pos) - spots[j].radius + spots[i].radius;
+			if (d > dj ) 
+			{
+				d = dj;
+				fi = i;
+			}
+		}
     }
     
     // d now equals distance to nearest spot...
-    if (d > RADIUS) {
-		alpha = 1.0;
-	} else {
-		if (d < INNER) {
-			alpha = 0.0;
-		} else {
-			alpha = (d - INNER) / (RADIUS - INNER);
+    // allowing for the different radii of all spotlights
+    if (fi != -1) {
+		
+		if (d > spots[fi].radius) 
+		{
+			alpha = 1.0;
+		}
+		else
+		{
+			if (d < spots[fi].inner) 
+			{
+				alpha = 0.0;
+			}
+			else 
+			{
+				alpha = (d - spots[fi].inner) / (spots[fi].radius - spots[fi].inner);
+			}
 		}
 	}
 	
-	// right hand side of screen is dimly lit, could make the
-	// threshold value user definable.
-	if (pos.x > screenWidth/2.0 && alpha > 0.9) {
-		alpha = 0.9;
-	}
+	// Right hand side of screen is dimly lit, 
+    // could make the threshold value user definable
+	if ((pos.x > screenWidth/2.0) && (alpha > 0.9)) alpha = 0.9;
 
 	// could make the black out colour user definable...
     gl_FragColor = vec4( 0, 0, 0, alpha);
diff --git a/examples/shaders/resources/shaders/glsl330/spotlight.fs b/examples/shaders/resources/shaders/glsl330/spotlight.fs
index f20d92a8..fe53ad61 100644
--- a/examples/shaders/resources/shaders/glsl330/spotlight.fs
+++ b/examples/shaders/resources/shaders/glsl330/spotlight.fs
@@ -9,36 +9,61 @@ out vec4 finalColor;
 
 // NOTE: Add here your custom variables
 
-#define     MAX_SPOTS			2
-#define		RADIUS				128
-#define		INNER				96
+#define     MAX_SPOTS			3
 
-uniform vec2 spots[MAX_SPOTS];      // Spotlight positions array
+struct Spot {
+    vec2 pos;		// window coords of spot
+    float inner;	// inner fully transparent centre radius
+    float radius;	// alpha fades out to this radius
+};
+
+uniform Spot spots[MAX_SPOTS];      // Spotlight positions array
 uniform float screenWidth;          // Width of the screen
 
 void main()
 {
-	float alpha = 0.0;
+	float alpha = 1.0;
     
 	// Get the position of the current fragment (screen coordinates!)
+	
 	vec2 pos = vec2(gl_FragCoord.x, gl_FragCoord.y);
 	
 	// Find out which spotlight is nearest
 	float d = 65000; // some high value
-	float di = 0;
+	int fi = -1; // found index
 
     for (int i = 0; i < MAX_SPOTS; i++)
     {
-		di = distance(pos, spots[i]);
-		if (d > di) d = di;
+		for (int j = 0; j < MAX_SPOTS; j++)
+		{
+			float dj = distance(pos, spots[j].pos) - spots[j].radius + spots[i].radius;
+			if (d > dj ) 
+			{
+				d = dj;
+				fi = i;
+			}
+		}
     }
     
     // d now equals distance to nearest spot...
-    if (d > RADIUS) alpha = 1.0;
-	else
-    {
-		if (d < INNER) alpha = 0.0;
-		else alpha = (d - INNER)/(RADIUS - INNER);
+    // allowing for the different radii of all spotlights
+    if (fi != -1) {
+		
+		if (d > spots[fi].radius) 
+		{
+			alpha = 1.0;
+		}
+		else
+		{
+			if (d < spots[fi].inner) 
+			{
+				alpha = 0.0;
+			}
+			else 
+			{
+				alpha = (d - spots[fi].inner) / (spots[fi].radius - spots[fi].inner);
+			}
+		}
 	}
 	
 	// Right hand side of screen is dimly lit,