Add GLSL shader node using PyOpenGL (#12148)

* adds support for executing simple glsl shaders
using moderngl package

* tidy

* Support multiple outputs

* Try fix build

* fix casing

* fix line endings

* convert to using PyOpenGL and glfw

* remove cpu support

* tidy

* add additional support for egl & osmesa backends

* fix ci
perf: only read required outputs

* add diagnostics, update mac initialization

* GLSL glueprints + node fixes (#12492)

* Add image operation blueprints

* Add channels

* Add glow

* brightness/contrast

* hsb

* add glsl shader update system

* shader nit iteration

* add multipass for faster blur

* more fixes

* rebuild blueprints

* print -> logger

* Add edge preserving blur

* fix: move _initialized flag to end of GLContext.__init__

Prevents '_vao' attribute error when init fails partway through
and subsequent calls skip initialization due to early _initialized flag.

* update valid ranges
- threshold 0-100
- step 0+

* fix value ranges

* rebuild node to remove extra inputs

* Fix gamma step

* clamp saturation in colorize instead of wrapping

* Fix crash on 1x1 px images

* rework description

* remove unnecessary f


Co-authored-by: Jedrzej Kosinski <kosinkadink1@gmail.com>
Co-authored-by: Hunter Senft-Grupp <hunter@comfy.org>

blueprints/.glsl/Brightness_and_Contrast_1.frag

@@ -0,0 +1,44 @@
+#version 300 es
+precision highp float;
+
+uniform sampler2D u_image0;
+uniform float u_float0; // Brightness slider -100..100
+uniform float u_float1; // Contrast slider -100..100
+
+in vec2 v_texCoord;
+out vec4 fragColor;
+
+const float MID_GRAY = 0.18;  // 18% reflectance
+
+// sRGB gamma 2.2 approximation
+vec3 srgbToLinear(vec3 c) {
+    return pow(max(c, 0.0), vec3(2.2));
+}
+
+vec3 linearToSrgb(vec3 c) {
+    return pow(max(c, 0.0), vec3(1.0/2.2));
+}
+
+float mapBrightness(float b) {
+    return clamp(b / 100.0, -1.0, 1.0);
+}
+
+float mapContrast(float c) {
+    return clamp(c / 100.0 + 1.0, 0.0, 2.0);
+}
+
+void main() {
+    vec4 orig = texture(u_image0, v_texCoord);
+
+    float brightness = mapBrightness(u_float0);
+    float contrast   = mapContrast(u_float1);
+
+    vec3 lin = srgbToLinear(orig.rgb);
+
+    lin = (lin - MID_GRAY) * contrast + brightness + MID_GRAY;
+
+    // Convert back to sRGB
+    vec3 result = linearToSrgb(clamp(lin, 0.0, 1.0));
+
+    fragColor = vec4(result, orig.a);
+}