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-rw-r--r--mesalib/src/mesa/tnl/t_draw.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/mesalib/src/mesa/tnl/t_draw.c b/mesalib/src/mesa/tnl/t_draw.c
index 741f0ed3f..a2ca6225b 100644
--- a/mesalib/src/mesa/tnl/t_draw.c
+++ b/mesalib/src/mesa/tnl/t_draw.c
@@ -125,6 +125,43 @@ convert_half_to_float(const struct gl_client_array *input,
}
}
+/**
+ * \brief Convert fixed-point to floating-point.
+ *
+ * In OpenGL, a fixed-point number is a "signed 2's complement 16.16 scaled
+ * integer" (Table 2.2 of the OpenGL ES 2.0 spec).
+ *
+ * If the buffer has the \c normalized flag set, the formula
+ * \code normalize(x) := (2*x + 1) / (2^16 - 1) \endcode
+ * is used to map the fixed-point numbers into the range [-1, 1].
+ */
+static void
+convert_fixed_to_float(const struct gl_client_array *input,
+ const GLubyte *ptr, GLfloat *fptr,
+ GLuint count)
+{
+ GLuint i, j;
+ const GLint size = input->Size;
+
+ if (input->Normalized) {
+ for (i = 0; i < count; ++i) {
+ const GLfixed *in = (GLfixed *) ptr;
+ for (j = 0; j < size; ++j) {
+ *fptr++ = (GLfloat) (2 * in[j] + 1) / (GLfloat) ((1 << 16) - 1);
+ }
+ ptr += input->StrideB;
+ }
+ } else {
+ for (i = 0; i < count; ++i) {
+ const GLfixed *in = (GLfixed *) ptr;
+ for (j = 0; j < size; ++j) {
+ *fptr++ = in[j] / (GLfloat) (1 << 16);
+ }
+ ptr += input->StrideB;
+ }
+ }
+}
+
/* Adjust pointer to point at first requested element, convert to
* floating point, populate VB->AttribPtr[].
*/
@@ -174,6 +211,9 @@ static void _tnl_import_array( struct gl_context *ctx,
case GL_HALF_FLOAT:
convert_half_to_float(input, ptr, fptr, count, sz);
break;
+ case GL_FIXED:
+ convert_fixed_to_float(input, ptr, fptr, count);
+ break;
default:
assert(0);
break;