port: fix blur shader on some older cards

port/fast3d/gfx_opengl.cpp

@@ -397,19 +397,14 @@ static struct ShaderProgram* gfx_opengl_create_and_load_new_shader(uint64_t shad
     if (cc_features.opt_blur) {
         // blur filter, used for menu backgrounds
         // used to be two for loops from 0 to 4, but apparently intel drivers crashed trying to unroll it
+        // used to have a const weight array, but apparently drivers for the GT620 don't like const array initializers
         append_line(fs_buf, &fs_len, R"(
-            const lowp float blurWeights[16] = float[16](
-                0.009947, 0.009641, 0.008778, 0.007509,
-                0.009641, 0.009345, 0.008508, 0.007278,
-                0.008778, 0.008508, 0.007747, 0.006626,
-                0.007509, 0.007278, 0.006626, 0.005668
-            );
             lowp vec4 hookTexture2D(in sampler2D t, in vec2 uv, in vec2 tsize) {
                 lowp vec4 cw = vec4(0.0);
                 for (int i = 0; i < 16; ++i) {
                     vec2 xy = vec2(float(i & 3), float(i >> 2));
-                    vec2 ofs = (vec2(-1.5) + xy) / tsize;
-                    cw += vec4(texture2D(t, uv + ofs).rgb * blurWeights[i], blurWeights[i]);
+                    lowp float w = 0.009947 - length(xy) * 0.001;
+                    cw += vec4(texture2D(t, uv + (vec2(-1.5) + xy) / tsize).rgb * w, w);
                 }
                 return vec4(cw.rgb / cw.a, 1.0);
             })"