diff options
| -rw-r--r-- | src/mesa/tnl/t_draw.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/src/mesa/tnl/t_draw.c b/src/mesa/tnl/t_draw.c index 858b8281da3..b1967e65417 100644 --- a/src/mesa/tnl/t_draw.c +++ b/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; |