vo_opengl: simplify the case without texture_rg

If GL_RED was not available, we used GL_ALPHA. But this is an
unnecessary complication, and it's easier to use GL_LUMINANCE instead.
With the latter, a texture will return the .r component set, and as long
as the shader doesn't look at the other components, the shader doesn't
need any changes.

Some of the changes added in 0e8fbdbd are now unneeeded.

Also, realign the entire gl_byte_formats_legacy table.

1 files changed, 9 insertions, 17 deletions

diff --git a/video/out/gl_video.c b/video/out/gl_video.c
index e7c2c46450..126decf4e7 100644
--- a/video/out/gl_video.c
+++ b/video/out/gl_video.c
@@ -245,18 +245,14 @@ static const struct fmt_entry gl_byte_formats_gles3[] = {
 };
 
 static const struct fmt_entry gl_byte_formats_legacy[] = {
-    {0, GL_ALPHA,   GL_ALPHA,   GL_UNSIGNED_BYTE},      // 1 x 8
-    {0, GL_LUMINANCE_ALPHA,
-                    GL_LUMINANCE_ALPHA,
-                                GL_UNSIGNED_BYTE},      // 2 x 8
-    {0, GL_RGB,     GL_RGB,     GL_UNSIGNED_BYTE},      // 3 x 8
-    {0, GL_RGBA,    GL_RGBA,    GL_UNSIGNED_BYTE},      // 4 x 8
-    {0, GL_ALPHA16, GL_ALPHA,   GL_UNSIGNED_SHORT},     // 1 x 16
-    {0, GL_LUMINANCE16_ALPHA16,
-                    GL_LUMINANCE_ALPHA,
-                                GL_UNSIGNED_SHORT},     // 2 x 16
-    {0, GL_RGB16,   GL_RGB,     GL_UNSIGNED_SHORT},     // 3 x 16
-    {0, GL_RGBA16,  GL_RGBA,    GL_UNSIGNED_SHORT},     // 4 x 16
+    {0, GL_LUMINANCE,           GL_LUMINANCE,       GL_UNSIGNED_BYTE}, // 1 x 8
+    {0, GL_LUMINANCE_ALPHA,     GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE}, // 2 x 8
+    {0, GL_RGB,                 GL_RGB,             GL_UNSIGNED_BYTE}, // 3 x 8
+    {0, GL_RGBA,                GL_RGBA,            GL_UNSIGNED_BYTE}, // 4 x 8
+    {0, GL_LUMINANCE16,         GL_LUMINANCE,       GL_UNSIGNED_SHORT},// 1 x 16
+    {0, GL_LUMINANCE16_ALPHA16, GL_LUMINANCE_ALPHA, GL_UNSIGNED_SHORT},// 2 x 16
+    {0, GL_RGB16,               GL_RGB,             GL_UNSIGNED_SHORT},// 3 x 16
+    {0, GL_RGBA16,              GL_RGBA,            GL_UNSIGNED_SHORT},// 4 x 16
 };
 
 static const struct fmt_entry gl_float16_formats[] = {
@@ -2246,11 +2242,9 @@ static void packed_fmt_swizzle(char w[5], const struct fmt_entry *texfmt,
 {
     const char *comp = "rgba";
 
-    // Normally, we work with GL_RED and GL_RG
+    // Normally, we work with GL_RG
     if (texfmt && texfmt->internal_format == GL_LUMINANCE_ALPHA)
         comp = "ragb";
-    if (texfmt && texfmt->internal_format == GL_ALPHA)
-        comp = "argb";
 
     for (int c = 0; c < 4; c++)
         w[c] = comp[MPMAX(fmt->components[c] - 1, 0)];
@@ -2290,8 +2284,6 @@ static bool init_format(int fmt, struct gl_video *init)
             plane_format[0] = find_tex_format(gl, (bits + 7) / 8, 1);
             for (int p = 1; p < desc.num_planes; p++)
                 plane_format[p] = plane_format[0];
-            if (!(init->gl->mpgl_caps & MPGL_CAP_TEX_RG) && desc.num_planes < 2)
-                snprintf(init->color_swizzle, sizeof(init->color_swizzle), "argb");
             goto supported;
         }
     }