add shaders for bars, remove waterfall

src/shaders/bars.frag

@@ -0,0 +1,12 @@
+#version 330 core
+
+in  float vVal;
+out vec4  fragColor;
+
+uniform sampler1D heatmap;
+
+void main()
+{
+    vec3 col = texture(heatmap, vVal).rgb;
+    fragColor = vec4(col, 1.0);
+}

src/shaders/bars.vert

@@ -0,0 +1,38 @@
+#version 330 core
+
+uniform float barHeights[96];
+uniform int   barCount;
+uniform float barWidth;
+uniform float gap;
+uniform float bottomY;
+uniform float topClip;
+
+out float vVal;
+
+void main()
+{
+    int bar    = gl_InstanceID;
+    int vertex = gl_VertexID;
+
+    float h = barHeights[bar];
+
+    float xLeft  = -1.0 + float(bar) * (barWidth + gap);
+    float xRight = xLeft + barWidth;
+
+    float regionH = topClip - bottomY;
+    float yTop    = bottomY + h * regionH;
+
+    vec2 corners[6];
+    corners[0] = vec2(xLeft,  bottomY);
+    corners[1] = vec2(xRight, bottomY);
+    corners[2] = vec2(xRight, yTop);
+    corners[3] = vec2(xLeft,  bottomY);
+    corners[4] = vec2(xRight, yTop);
+    corners[5] = vec2(xLeft,  yTop);
+
+    vec2 pos = corners[vertex];
+
+    vVal = (pos.y - bottomY) / regionH;
+
+    gl_Position = vec4(pos, 0.0, 1.0);
+}