diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/mesa/drivers/dri/i915/i915_fragprog.c | 77 |
1 files changed, 54 insertions, 23 deletions
diff --git a/src/mesa/drivers/dri/i915/i915_fragprog.c b/src/mesa/drivers/dri/i915/i915_fragprog.c index 0a643719f8..cbac07cde1 100644 --- a/src/mesa/drivers/dri/i915/i915_fragprog.c +++ b/src/mesa/drivers/dri/i915/i915_fragprog.c @@ -43,11 +43,19 @@ #include "i915_context.h" #include "i915_program.h" -static const GLfloat sin_quad_constants[4] = { - 4.0, - -4.0, - 2.0, - -1.0 +static const GLfloat sin_quad_constants[2][4] = { + { + 2.0, + -1.0, + .5, + 0.0 + }, + { + 4.0, + -4.0, + 1.0 / (2.0 * M_PI), + .2225 + } }; static const GLfloat sin_constants[4] = { 1.0, @@ -341,7 +349,7 @@ upload_program(struct i915_fragment_program *p) while (1) { GLuint src0, src1, src2, flags; - GLuint tmp = 0, consts = 0; + GLuint tmp = 0, consts0 = 0, consts1 = 0; switch (inst->Opcode) { case OPCODE_ABS: @@ -690,15 +698,16 @@ upload_program(struct i915_fragment_program *p) case OPCODE_SIN: src0 = src_vector(p, &inst->SrcReg[0], program); tmp = i915_get_utemp(p); - consts = i915_emit_const4fv(p, sin_quad_constants); + consts0 = i915_emit_const4fv(p, sin_quad_constants[0]); + consts1 = i915_emit_const4fv(p, sin_quad_constants[1]); /* Reduce range from repeating about [-pi,pi] to [-1,1] */ i915_emit_arith(p, A0_MAD, tmp, A0_DEST_CHANNEL_X, 0, src0, - i915_emit_const1f(p, 1.0 / (2.0 * M_PI)), - i915_emit_const1f(p, .5)); + swizzle(consts1, Z, ZERO, ZERO, ZERO), /* 1/(2pi) */ + swizzle(consts0, Z, ZERO, ZERO, ZERO)); /* .5 */ i915_emit_arith(p, A0_FRC, tmp, A0_DEST_CHANNEL_X, 0, tmp, 0, 0); @@ -706,19 +715,15 @@ upload_program(struct i915_fragment_program *p) A0_MAD, tmp, A0_DEST_CHANNEL_X, 0, tmp, - swizzle(consts, Z, ZERO, ZERO, ZERO), /* 2 */ - swizzle(consts, W, ZERO, ZERO, ZERO)); /* -1 */ + swizzle(consts0, X, ZERO, ZERO, ZERO), /* 2 */ + swizzle(consts0, Y, ZERO, ZERO, ZERO)); /* -1 */ - /* Compute sin using a quadratic. While it has increased total - * error over the range, it does give continuity that the 4-component - * Taylor series lacks when repeating the range due to its - * sin(PI) != 0 behavior. + /* Compute sin using a quadratic and quartic. It gives continuity + * that repeating the Taylor series lacks every 2*pi, and has + * reduced error. * * The idea was described at: * http://www.devmaster.net/forums/showthread.php?t=5784 - * - * If we're concerned about the error of this approximation, we should - * probably incorporate a second pass to include a x**4 factor. */ /* tmp.y = abs(tmp.x); {x, abs(x), 0, 0} */ @@ -737,15 +742,41 @@ upload_program(struct i915_fragment_program *p) tmp, 0); - /* result = tmp.xy DP sin_quad_constants.xy */ + /* tmp.x = tmp.xy DP sin_quad_constants[2].xy */ i915_emit_arith(p, A0_DP3, + tmp, A0_DEST_CHANNEL_X, 0, + tmp, + swizzle(consts1, X, Y, ZERO, ZERO), + 0); + + /* tmp.x now contains a first approximation (y). Now, weight it + * against tmp.y**2 to get closer. + */ + i915_emit_arith(p, + A0_MAX, + tmp, A0_DEST_CHANNEL_Y, 0, + swizzle(tmp, ZERO, X, ZERO, ZERO), + negate(swizzle(tmp, ZERO, X, ZERO, ZERO), 0, 1, 0, 0), + 0); + + /* tmp.y = tmp.x * tmp.y - tmp.x; {y, y * abs(y) - y, 0, 0} */ + i915_emit_arith(p, + A0_MAD, + tmp, A0_DEST_CHANNEL_Y, 0, + swizzle(tmp, ZERO, X, ZERO, ZERO), + swizzle(tmp, ZERO, Y, ZERO, ZERO), + negate(swizzle(tmp, ZERO, X, ZERO, ZERO), 0, 1, 0, 0)); + + /* result = .2225 * tmp.y + tmp.x =.2225(y * abs(y) - y) + y= */ + i915_emit_arith(p, + A0_MAD, get_result_vector(p, inst), get_result_flags(inst), 0, - tmp, - swizzle(i915_emit_const4fv(p, sin_quad_constants), - X, Y, ZERO, ZERO), - 0); + swizzle(consts1, W, W, W, W), + swizzle(tmp, Y, Y, Y, Y), + swizzle(tmp, X, X, X, X)); + break; case OPCODE_SLT: |